Processes of producing a fermentation product

ABSTRACT

The invention relates to a process of process of producing a fermentation product, comprising: liquefying a starch-containing material to dextrins with an alpha-amylase in the presence of an asparaginase and/or an amino acid oxidase; saccharifying the dextrins to a sugar with a glucoamylase; and fermenting the sugar using a fermenting organism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/988,103 filed Aug. 27, 2013, now allowed, which is a 35 U.S.C. 371 national application of PCT/US2011/060696 filed Nov. 15, 2011, which claims priority or the benefit under 35 U.S.C. 119 of U.S. provisional application No. 61/415,572 filed Nov. 19, 2010, the contents of which are fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to methods of producing a fermentation product from plant material using one or more fermenting organisms; compositions; transgenic plants; and modified fermenting organisms, that can be used in methods and/or processes of the invention.

BACKGROUND OF THE INVENTION

A vast number of commercial products that are difficult to produce synthetically are today produced by fermenting organisms. Such products include alcohols (e.g., butanol, ethanol, methanol, 1,3-propanediol); organic acids (e.g., acetic acid, citric acid, gluconate, gluconic acid, itaconic acid, lactic acid, succinic acid, 2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g., H₂ and CO₂), and more complex compounds, including, for example, antibiotics (e.g., penicillin and tetracycline); enzymes; vitamins (e.g., riboflavin, B₁₂, beta-carotene); and hormones. Fermentation is also commonly used in the consumable alcohol (e.g., beer and wine), dairy (e.g., in the production of yogurt and cheese), leather, and tobacco industries.

A vast number of processes of producing fermentation products, such as ethanol, by fermentation of sugars provided by degradation of starch-containing materials are known in the art.

However, production of fermentation products, such as ethanol, from such plant materials is still too costly. Therefore, there is a need for providing processes that can increase the yield of the fermentation product and thereby reduce the production costs.

It is an object of the present invention to provide an improved process for producing a fermentation product.

SUMMARY OF THE INVENTION

The present invention relates to a process of producing a fermentation product, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase;

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(c) fermenting the sugar using a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme.

The present invention also relates to a process of producing a fermentation product, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase;

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(d) fermenting the sugar using a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a dextrin, comprising

(a) liquefying a starch-containing material to the dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) recovering the dextrin.

The present invention also relates to a process of producing a fermentation product, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase;

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(d) fermenting the sugar using a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase; and

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme.

The present invention also relates to a process of producing a dextrin, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase.

The present invention also relates to a process of producing a fermentation product, comprising converting a starch-containing material to a dextrin with an alpha-amylase; saccharifying the dextrin to a sugar with a glucoamylase; and fermenting the sugar using a fermenting organism in the presence of an amino acid oxidase, an arginase, and/or an asparaginase in a single step at a temperature below the initial gelatinization temperature of the starch-containing material.

The present invention also relates to a process of producing a fermentation product, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) producing molasses from the plant extract;

(c) diluting the molasses; and

(d) fermenting the diluted molasses with a fermenting organism to produce ethanol.

The present invention also relates to a process of producing a fermentation product, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) fermenting the treated plant extract with a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) recovering the sugar from the treated plant extract.

The present invention also relates to a process of producing sucrose, comprising:

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) clarification of the plant extract;

(c) concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup containing sucrose;

(d) crystallization of sucrose from the syrup; and

(e) recovering sucrose.

The present invention also relates to a composition comprising (a) an asparaginase, an arginase, and/or amino acid oxidase, (b) a glucoamylase and (c) an alpha-amylase.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Alpha-amylases (alpha-1,4-glucan-4-glucanohydrolases, EC 3.2.1.1) are a group of enzymes, which catalyze the hydrolysis of starch and other linear and branched 1,4-glucosidic oligo- and polysaccharides.

Amino acid oxidases (L-amino acid oxidase, EC 1.4.3.2 and D-amino acid oxidase, EC1.4.3.3) are a group of enzymes which catalyze the following reaction: L-amino acid+H₂O+O₂

alpha 2-oxo acid+NH₃+H₂O₂

Arginases (L-Arginine aminohydrolase, EC 3.5.3.1) are a group of enzymes which catalyze the following reaction: L-arginine+H₂O=Ornithine+Urea

Asparaginases are enzymes of EC 3.5.1.1 (asparaginase or L-asparagine amidohydrolase) and EC 3.5.1.38 (glutamin-asparaginase or glutaminase-asparaginase), which catalyze the following reaction: L-asparagine+H₂O=L-aspartate+NH₄ ⁺

Fragment: The term “fragment” means a polypeptide having one or more (several) amino acids deleted from the amino and/or carboxyl terminus of a mature polypeptide; wherein the fragment has enzyme activity.

Glucoamylases (glucan 1,4-α-glucosidase, EC 3.2.1.3) are a group of enzymes, which catalyze the hydrolysis of terminal (1→4)-linked α-D-glucose residues successively from non-reducing ends of the chains with release of β-D-glucose.

Isolated: The terms “isolated” and “purified” mean a polypeptide or polynucleotide that is removed from at least one component with which it is naturally associated. For example, a polypeptide or variant may be at least 1% pure, e.g., at least 5% pure, at least 10% pure, at least 20% pure, at least 40% pure, at least 60% pure, at least 80% pure, and at least 90% pure, as determined by SDS-PAGE and a polynucleotide may be at least 1% pure, e.g., at least 5% pure, at least 10% pure, at least 20% pure, at least 40% pure, at least 60% pure, at least 80% pure, at least 90% pure, and at least 95% pure, as determined by agarose electrophoresis.

Mature polypeptide: The term “mature polypeptide” means a polypeptide in its final form following translation and any post-translational modifications, such as N-terminal processing, C-terminal truncation, glycosylation, phosphorylation, etc.

Parent Enzyme: The term “parent” means an enzyme to which an alteration is made to produce a variant. The parent may be a naturally occurring (wild-type) polypeptide or a variant thereof.

Sequence Identity: The relatedness between two amino acid sequences or between two nucleotide sequences is described by the parameter “sequence identity”.

For purposes of the present invention, the degree of sequence identity between two amino acid sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends Genet. 16: 276-277), preferably version 3.0.0 or later. The optional parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix. The output of Needle labeled “longest identity” (obtained using the -nobrief option) is used as the percent identity and is calculated as follows: (Identical Residues×100)/(Length of Alignment−Total Number of Gaps in Alignment)

For purposes of the present invention, the degree of sequence identity between two deoxyribonucleotide sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, supra) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, supra), preferably version 3.0.0 or later. The optional parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EDNAFULL (EMBOSS version of NCBI NUC4.4) substitution matrix. The output of Needle labeled “longest identity” (obtained using the -nobrief option) is used as the percent identity and is calculated as follows: (Identical Deoxyribonucleotides×100)/(Length of Alignment−Total Number of Gaps in Alignment)

Variant: The term “variant” means a polypeptide comprising an alteration, i.e., a substitution, insertion, and/or deletion, at one or more (several) positions. A substitution means a replacement of an amino acid occupying a position with a different amino acid; a deletion means removal of an amino acid occupying a position; and an insertion means adding 1-5 amino acids adjacent to an amino acid occupying a position.

Wild-Type Enzyme: The term “wild-type” enzyme means an enzyme expressed by a naturally occurring microorganism, such as a bacterium, yeast, or filamentous fungus found in nature.

Processes for Producing Fermentation Products, Dextrins, and Sugars from Starch-Containing Materials

The present invention relates to a process of producing a fermentation product, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase;

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(c) fermenting the sugar using a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme.

The present invention also relates to a process of producing a dextrin, comprising

(a) liquefying a starch-containing material to the dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) recovering the dextrin.

The present invention also relates to a process of producing a fermentation product, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase;

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(d) fermenting the sugar using a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase; and

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme.

The present invention also relates to a process of producing a dextrin, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase.

Starch is formed within plant cells as tiny granules insoluble in water. When put in cold water, the starch granules may absorb a small amount of the liquid and swell. At temperatures up to 50° C. to 75° C. the swelling may be reversible. However, with higher temperatures an irreversible swelling called “gelatinization” begins. Granular starch to be processed may be a highly refined starch quality, preferably at least 90%, at least 95%, at least 97% or at least 99.5% pure or it may be a more crude starch-containing materials comprising (e.g., milled) whole grains including non-starch fractions such as germ residues and fibers. The raw material, such as whole grains, may be reduced in particle size, e.g., by milling, in order to open up the structure and allowing for further processing. Two processes are preferred according to the invention: wet and dry milling. In dry milling whole kernels are milled and used. Wet milling gives a good separation of germ and meal (starch granules and protein) and is often applied at locations where the starch hydrolyzate is used in the production of, e.g., syrups. Both dry and wet milling are well known in the art of starch processing and may be used in a process of the invention. In an embodiment the particle size is reduced to between 0.05-3.0 mm, preferably 0.1-0.5 mm, or so that at least 30%, preferably at least 50%, more preferably at least 70%, even more preferably at least 90% of the starch-containing material fits through a sieve with a 0.05-3.0 mm screen, preferably 0.1-0.5 mm screen.

The starch-containing material may be used to produce a sugar, a dextrin, or a fermentation product. Generally, the sugar-containing material is liquefied to a dextrin with an alpha-amylase, which is then followed by saccharification (a process which converts the dextrin to a sugar) and fermentation (a process which converts the sugar to a fermentation product).

In an embodiment, the starch-containing material is treated with an amino acid oxidase, an arginase, and/or an asparaginase prior to liquefaction. This treatment may be carried out at any pH and temperature suitable for enzyme activity for a period of time to allow for the enzymatic reaction to take place. In an embodiment, the temperature is in the range of 20-75° C., e.g., 20-65° C. or 40-60° C.; the pH is in the range of 4.5-6.5; and the period of time is in the range of 5 minutes-2 hours, e.g., 5 minutes-1 hour.

In an embodiment, an asparaginase is added to the starch-containing material prior to liquefaction. In another embodiment, an arginase is added to the starch-containing material prior to liquefaction. In another embodiment, an amino acid oxidase is added to the starch-containing material prior to liquefaction. In another embodiment, an asparaginase, an arginase, and an amino acid oxidase are added to the starch-containing material prior to liquefaction.

An asparaginase and/or an amino acid oxidase also may be added during liquefaction. In an embodiment, an asparaginase is added during liquefaction. In another embodiment, an arginase is added during liquefaction. In another embodiment, an amino acid oxidase is added during liquefaction. In another embodiment, an asparaginase, an arginase, and an amino acid oxidase are present during liquefaction.

Liquefaction is carried out in the presence of an alpha-amylase, preferably a bacterial alpha-amylase and/or acid fungal alpha-amylase. In an embodiment, a phytase is also present during liquefaction.

During a typical liquefaction, the long-chained starch is degraded into branched and linear shorter units (maltodextrins) by an alpha-amylase. Liquefaction may be carried out as a three-step hot slurry process. The slurry is heated to between 60-95° C. (e.g., 77-86° C., 80-85° C., or 83-85° C.) and an alpha-amylase(s) is (are) added to initiate liquefaction (thinning). The liquefaction process is carried out at 85° C. for 1-2 hours. The pH is generally between 5.5 and 6.2. In order to ensure optimal enzyme stability under these conditions, 1 mM of calcium is optionally added (to provide about 40 ppm free calcium ions). After such treatment, the liquefied starch will have a “dextrose equivalent” (DE) of 10-15.

The slurry may be subsequently jet-cooked at between 95-140° C., e.g., 105-125° C., for about 1-15 minutes, e.g., about 3-10 minutes, especially around 5 minutes. The slurry is then cooled to 60-95° C. and more alpha-amylase(s) is (are) added to obtain the final hydrolysis (secondary liquefaction). The jet-cooking process is carried out at pH 4.5-6.5, typically at a pH between 5 and 6. The alpha-amylase may be added as a single dose, e.g., before jet cooking.

Saccharification may be carried out using conditions well known in the art with a glucoamylase or a beta-amylase and optionally a debranching enzyme, such as an isoamylase or a pullulanase. For instance, a full saccharification step may last from about 24 to about 72 hours, however, it is also common to do a pre-saccharification of typically 40-90 minutes at a temperature between 30-65° C., typically about 60° C., followed by complete saccharification during fermentation in a simultaneous saccharification and fermentation (SSF) process. Saccharification is typically carried out at a temperature in the range of 20-75° C., e.g., 25-65° C. and 40-70° C., typically around 60° C., and at a pH between about 4 and 5, normally at about pH 4.5.

The saccharification and fermentation steps may be carried out either sequentially or simultaneously. In an embodiment, saccharification and fermentation are performed simultaneously (SSF), in which there is no holding stage for the saccharification, meaning that a fermenting organism, such as yeast, and enzyme(s) are added together. SSF is typically carried out at a temperature of 20-40° C., e.g., 26-34° C., preferably around 32° C., when the fermentation organism is yeast, such as a strain of Saccharomyces cerevisiae, and the fermentation product is ethanol.

Other fermentation products may be fermented at conditions and temperatures well known to persons skilled in the art, suitable for the fermenting organism in question. The temperature may be adjusted up or down during fermentation.

The dextrin may be recovered by methods well known in the art.

The sugar may be recovered by methods well known in the art.

The fermentation product may be recovered by methods well known in the art, e.g., by distillation.

In a particular embodiment, the process of the invention further comprises, prior to the conversion of a starch-containing material to dextrins and/or the treatment of the starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase, the steps of:

(x) reducing the particle size of the starch-containing material; and

(y) forming a slurry comprising the starch-containing material and water.

Methods for reducing the particle size of the starch containing material are known to those skilled in the art. In an embodiment, the starch-containing material is milled to reduce the particle size.

The aqueous slurry may contain from 10-55 wt. % dry solids (DS), preferably 25-45 wt. % dry solids (DS), more preferably 30-40 wt. % dry solids (DS) of starch-containing material.

Processes for Producing Fermentation Products from Ungelatinized Starch-Containing Materials

The present invention also relates to a process for producing a fermentation product from a starch-containing material without gelatinization (often referred to as “without cooking”) of the starch-containing material. In an embodiment, the process includes saccharifying the (e.g., milled) starch-containing material below the initial gelatinization temperature, preferably in the presence of an alpha-amylase and/or a carbohydrate-source generating enzyme(s) (saccharifying enzyme(s)) to produce sugars that can be fermented into the fermentation product by a fermenting organism.

Accordingly, this aspect of the invention relates to a process of producing a fermentation product, comprising converting a starch-containing material to a dextrin with an alpha-amylase; saccharifying the dextrin to a sugar with a glucoamylase; and fermenting the sugar using a fermenting organism in the presence of an amino acid oxidase, an arginase, and/or an asparaginase in a single step at a temperature below the initial gelatinization temperature of the starch-containing material.

The term “initial gelatinization temperature” means the lowest temperature at which starch gelatinization commences. In general, starch heated in water begins to gelatinize between about 50° C. and 75° C.; the exact temperature of gelatinization depends on the specific starch and can readily be determined by the skilled artisan. Thus, the initial gelatinization temperature may vary according to the plant species, to the particular variety of the plant species as well as with the growth conditions. The initial gelatinization temperature of a given starch-containing material may be determined as the temperature at which birefringence is lost in 5% of the starch granules using the method described by Gorinstein and Lii, 1992, Starch/Stärke 44(12): 461-466.

The process of the present invention may further comprise recovering the fermentation product, e.g., by distillation.

The starch-containing material may be a slurry, such as granular starch, having 10-55 wt. % dry solids (DS), preferably 25-45 wt. % dry solids, more preferably 30-40 wt. % dry solids of starch-containing material may be prepared. The slurry may include water and/or process waters, such as stillage (backset), scrubber water, evaporator condensate or distillate, side-stripper water from distillation, or process water from other fermentation product plants. Because the process is carried out below the initial gelatinization temperature and thus no significant viscosity increase takes place, high levels of stillage may be used if desired. In an embodiment the aqueous slurry contains from about 1 to about 70 vol. %, preferably 15-60 vol. %, especially from about 30 to 50 vol. % water and/or process waters, such as stillage (backset), scrubber water, evaporator condensate or distillate, side-stripper water from distillation, or process water from other fermentation product plants, or combinations thereof, or the like.

The starch-containing material may be prepared by reducing the particle size, preferably by dry or wet milling, to 0.05-3.0 mm, preferably 0.1-0.5 mm. After being subjected to a method or process of the invention at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the dry solids in the starch-containing material is converted into a soluble starch hydrolyzate.

The process of this aspect of the invention is conducted at a temperature below the initial gelatinization temperature, e.g., a temperature in the range between 25-40° C., such as 25-40° C., 29-35° C., 30-34° C., such as around 32° C. One skilled in the art can easily determine suitable process conditions.

The process of the invention may be carried out at a pH from about 3 and 7, e.g., 3.5 to 6 or 4 to 5.

In an embodiment fermentation is carried out so that the sugar level, such as glucose level, is kept at a low level, such as below 6 wt. %, below about 3 wt. %, below about 2 wt. %, below about 1 wt. %., below about 0.5 wt. %, below 0.25% wt. %, or below about 0.1 wt. %. Such low levels of sugar can be accomplished by simply employing adjusted quantities of enzyme and fermenting organism. A skilled person in the art can easily determine which doses/quantities of enzyme and fermenting organism to use. The employed quantities of enzyme and fermenting organism may also be selected to maintain low concentrations of maltose in the fermentation broth. For instance, the maltose level may be kept below about 0.5 wt. %, such as below about 0.2 wt. %.

Starch-Containing Materials

Any suitable starch-containing starting material may be used in a process of the present invention. The starting material is generally selected based on the desired fermentation product. Examples of starch-containing starting materials, suitable for use in the processes of the present invention, include barley, beans, cassava, cereals, corn, milo, peas, potatoes, rice, rye, sago, sorghum, sweet potatoes, tapioca, wheat, and whole grains, or any mixture thereof. The starch-containing material may also be a waxy or non-waxy type of corn and barley.

Production of Fermentation Products and Sugars from a Plant Extract

The present invention also relates to a process of producing a sugar and/or a fermentation product such as ethanol, from a plant extract containing amino acid(s) and soluble sugar(s) (e.g., fructose, galactose, glucose, maltose, sucrose, and/or oligomers thereof), e.g., sugarcane, comprising applying an asparaginase and/or an amino acid oxidase to the plant extract.

In particular, the present invention relates to a process of producing a fermentation product, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) producing molasses from the plant extract;

(c) diluting the molasses; and

(d) fermenting the diluted molasses with a fermenting organism to produce ethanol.

The present invention also relates to a process of producing a fermentation product, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) fermenting the treated plant extract with a fermenting organism to produce the fermentation product.

The present invention also relates to a process of producing a sugar, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) recovering the sugar from the treated plant extract.

The present invention also relates to a process of producing sucrose, comprising:

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) clarification of the plant extract;

(c) concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup containing sucrose;

(d) crystallization of sucrose from the syrup; and

(e) recovering sucrose.

The sugar may be any sugar including but not limited to fructose, galactose, glucose, maltose, or sucrose.

Sugarcane is any of 6 to 37 species of tall perennial grasses of the genus Saccharum (family Poaceae, tribe Andropogoneae). Traditionally, sugarcane processing requires two stages. Mills extract raw sugar from freshly harvested cane, and sometimes bleach the sugar to make “mill white” sugar for local consumption. Refineries then produce refined white sugar, which is 99% sucrose.

The mill washes, chops, and uses revolving knives to shred the cane. Shredded cane is repeatedly mixed with water and crushed between rollers called crushers or diffusers to produce raw sugarcane juice. The raw sugarcane juice contains 10-15% sucrose, and the remaining fibrous solids, called bagasse, are burned for fuel. The cane juice is next mixed with lime to adjust its pH to 7. This mixing arrests sucrose's decay into glucose and fructose, and precipitates some impurities. The mixture then sits, allowing the lime and other suspended solids to settle, resulting in clarified juice. Other methods for clarifying sugarcane juice such as sulfitation and carbonation are known in the art. The clarified juice is concentrated in a multiple-effect evaporator to make a syrup containing about 60 wt. % sucrose. This syrup is further concentrated under vacuum until it becomes supersaturated, and then seeded with crystalline sugar. On cooling, more sugar crystallizes from the syrup. A centrifuge separates sucrose from the molasses. Additional crystallizations extract more sucrose; the final residue is called blackstrap.

After clarification, water is removed from the sugarcane juice by a multistep evaporation process. The leftover from this process, not viable for sucrose extraction, is called molasses and is commonly used as a substrate for fuel ethanol production.

In a process of the present invention, the plant extract is treated with an amino acid oxidase, an arginase, and/or an asparaginase, and molasses is produced from the treated plant extract. Molasses is produced by clarification of the plant extract; concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup; and crystallization of sucrose from the syrup to form the molasses. The molasses is then diluted, e.g., with water or plant extract juice (e.g., sugarcane juice), and the diluted molasses is fermented to produce a fermentation product.

The plant extract may be treated with an amino acid oxidase, an arginase, and/or an asparaginase in any step prior to evaporation. For example, the plant extract may be treated with an amino acid oxidase, an arginase, and/or an asparaginase during juice extraction, crushing, juice recovery, and/or juice clarification. Thus, the amino acid oxidase, the arginase, and/or the asparaginase may be added during the milling process and/or in the clarification steps.

The process of the present invention may further comprise recovering the fermentation product.

The process of the present invention may further comprise recovering the sugar. The sugar may be recovered by any process known in the art. For example, sucrose may be recovered by a process comprising

(x) clarification of the plant extract;

(y) concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup; and

(z) crystallization of sucrose from the syrup.

As explained above, typically, mills run the raw juice clarification for sugar and/or ethanol at a pH of around 7 to minimize Maillard product formation. Another benefit of the process of the present invention is that the raw juice may be clarified for sugar and/or ethanol production at a more alkaline pH such as a pH of 7.5-9, e.g., 8-9. By using an amino acid oxidase, an arginase, and/or an asparaginase to avoid Maillard product formation, a higher pH can be used, which improves the clarification performance in terms of quality (sugar brightness and/or juice lighter), yield (decreases the amount of sugar which is lost in the refinery process) and productivity (decreases the clarification hold time).

The plant extract may be sweet sorghum, sugar beets, sugar cane, or any mixture thereof. In particular, the plant extract may be raw sugarcane juice or clarified sugarcane juice.

Fermentation Products

The term “fermentation product” means a product produced by a method or process including fermenting using a fermenting organism. Fermentation products include alcohols (e.g., ethanol, methanol, butanol); organic acids (e.g., citric acid, acetic acid, itaconic acid, lactic acid, succinic acid, gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid); gases (e.g., H₂ and CO₂); antibiotics (e.g., penicillin and tetracycline); enzymes; vitamins (e.g., riboflavin, B₁₂, beta-carotene); and hormones. In a preferred embodiment the fermentation product is ethanol, e.g., fuel ethanol; drinking ethanol, i.e., potable neutral spirits; or industrial ethanol or products used in the consumable alcohol industry (e.g., beer and wine), dairy industry (e.g., fermented dairy products), leather industry and tobacco industry. Preferred beer types comprise ales, stouts, porters, lagers, bitters, malt liquors, happoushu, high-alcohol beer, low-alcohol beer, low-calorie beer or light beer.

Fermenting Organisms

The term “fermenting organism” refers to any organism, including bacterial and fungal organisms, such as yeast and filamentous fungi, suitable for producing a desired fermentation product. Suitable fermenting organisms according to the invention are able to ferment, i.e., convert, fermentable sugars, such as arabinose, fructose, glucose, maltose, mannose, or xylose, directly or indirectly into the desired fermentation product.

Examples of fermenting organisms include fungal organisms such as yeast. Preferred yeast include strains of Saccharomyces, in particular Saccharomyces cerevisiae or Saccharomyces uvarum; strains of Pichia, in particular Pichia stipitis such as Pichia stipitis CBS 5773 or Pichia pastoris; strains of Candida, in particular Candida arabinofermentans, Candida boidinii, Candida diddensii, Candida shehatae, Candida sonorensis, Candida tropicalis, or Candida utilis. Other fermenting organisms include strains of Hansenula, in particular Hansenula anomala or Hansenula polymorpha; strains of Kluyveromyces, in particular Kluyveromyces fragilis or Kluyveromyces marxianus; and strains of Schizosaccharomyces, in particular Schizosaccharomyces pombe.

Preferred bacterial fermenting organisms include strains of Escherichia, in particular Escherichia coli, strains of Zymomonas, in particular Zymomonas mobilis, strains of Zymobacter, in particular Zymobactor palmae, strains of Klebsiella in particular Klebsiella oxytoca, strains of Leuconostoc, in particular Leuconostoc mesenteroides, strains of Clostridium, in particular Clostridium butyricum, strains of Enterobacter, in particular Enterobacter aerogenes, and strains of Thermoanaerobacter, in particular Thermoanaerobacter BG1L1 (Appl. Microbiol. Biotech. 77: 61-86), Thermoanarobacter ethanolicus, Thermoanaerobacter mathranii, or Thermoanaerobacter thermosaccharolyticum. Strains of Lactobacillus are also envisioned as are strains of Corynebacterium glutamicum R, Bacillus thermoglucosidaisus, and Geobacillus thermoglucosidasius.

In an embodiment the fermenting organism is a C6 sugar fermenting organism, such as a strain of, e.g., Saccharomyces cerevisiae.

In one embodiment the fermenting organism is added to the fermentation medium so that the viable fermenting organism, such as yeast, count per mL of fermentation medium is in the range from 10⁵ to 10¹², preferably from 10⁷ to 10¹⁰, especially about 5×10⁷.

Yeast is the preferred fermenting organism for ethanol fermentation. Preferred are strains of Saccharomyces, especially strains of the species Saccharomyces cerevisiae, preferably strains which are resistant towards high levels of ethanol, i.e., up to, e.g., about 10, 12, 15 or 20 vol. % or more ethanol.

Commercially available yeast include LNF SA-1, LNF BG-1, LNF PE-2, and LNF CAT-1 (available from LNF Brazil), RED STAR™ and ETHANOL RED™ yeast (available from Fermentis/Lesaffre, USA), FALI (available from Fleischmann's Yeast, USA), SUPERSTART and THERMOSACC™ fresh yeast (available from Ethanol Technology, WI, USA), BIOFERM AFT and XR (available from NABC—North American Bioproducts Corporation, GA, USA), GERT STRAND (available from Gert Strand AB, Sweden), and FERMIOL (available from DSM Specialties).

According to the invention the fermenting organism capable of producing a desired fermentation product from fermentable sugars is preferably grown under precise conditions at a particular growth rate. When the fermenting organism is introduced into/added to the fermentation medium the inoculated fermenting organism pass through a number of stages. Initially growth does not occur. This period is referred to as the “lag phase” and may be considered a period of adaptation. During the next phase referred to as the “exponential phase” the growth rate gradually increases. After a period of maximum growth the rate ceases and the fermenting organism enters “stationary phase”. After a further period of time the fermenting organism enters the “death phase” where the number of viable cells declines.

Fermentation

The fermentation conditions are determined based on, e.g., the kind of plant material, the available fermentable sugars, the fermenting organism(s) and/or the desired fermentation product. One skilled in the art can easily determine suitable fermentation conditions. The fermentation may according to the invention be carried out at conventionally used conditions. Preferred fermentation processes are anaerobic processes.

For example, fermentations may be carried out at temperatures as high as 75° C., e.g., between 40-70° C., such as between 50-60° C. However, bacteria with a significantly lower temperature optimum down to around room temperature (around 20° C.) are also known. Examples of suitable fermenting organisms can be found in the “Fermenting Organisms” section above.

For ethanol production using yeast, the fermentation may go on for 24 to 96 hours, in particular for 35 to 60 hours. In an embodiment the fermentation is carried out at a temperature between 20 to 40° C., preferably 26 to 34° C., in particular around 32° C. In an embodiment the pH is from pH 3 to 6, preferably around pH 4 to 5.

Other fermentation products may be fermented at temperatures known to the skilled person in the art to be suitable for the fermenting organism in question.

Fermentation is typically carried out at a pH in the range between 3 and 7, preferably from pH 3.5 to 6, such as around pH 5. Fermentations are typically ongoing for 6-96 hours.

The processes of the invention may be performed as a batch or as a continuous process. Fermentations may be conducted in an ultrafiltration system wherein the retentate is held under recirculation in the presence of solids, water, and the fermenting organism, and wherein the permeate is the desired fermentation product containing liquid. Equally contemplated are methods/processes conducted in continuous membrane reactors with ultrafiltration membranes and where the retentate is held under recirculation in presence of solids, water, and the fermenting organism(s) and where the permeate is the fermentation product containing liquid.

After fermentation the fermenting organism may be separated from the fermented slurry and recycled.

Fermentation Medium

The phrase “fermentation media” or “fermentation medium” refers to the environment in which fermentation is carried out and comprises the fermentation substrate, that is, the carbohydrate source that is metabolized by the fermenting organism(s).

The fermentation medium may comprise other nutrients and growth stimulator(s) for the fermenting organism(s). Nutrient and growth stimulators are widely used in the art of fermentation and include nitrogen sources, such as ammonia; vitamins and minerals, or combinations thereof.

Recovery

Subsequent to fermentation, the fermentation product may be separated from the fermentation medium. The fermentation medium may be distilled to extract the desired fermentation product or the desired fermentation product may be extracted from the fermentation medium by micro or membrane filtration techniques. Alternatively, the fermentation product may be recovered by stripping. Methods for recovery are well known in the art.

Enzymes

The enzyme(s) described below are to be used in an “effective amount” in the processes of the present invention.

Asparaginases

The asparaginase may be an enzyme of EC 3.5.1.1 (asparaginase or L-asparagine amidohydrolase) or EC 3.5.1.38 (glutamin-asparaginase or glutaminase-asparaginase).

The asparaginase may be a microbial asparaginase, e.g., an asparaginase derived from a bacterium, an archaeon or a fungus. For example, the asparaginase may be derived from Archaea, Aspergillus, Candida, Erwinia, Fusarium, or Saccharomyces. In particular, the asparaginase may be derived from Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus oryzae, Candida utilis, Erwinia chrysanthemii, Escherichia coli, Fusarium graminearum, Penicillium citrinum, or Saccharomyces cerevisiae.

In an embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 1 (an Aspergillus oryzae asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 1; or is a fragment of SEQ ID NO: 1 which has asparaginase activity. Fragments of SEQ ID NO: 1 include the sequences of amino acids 27-378, 30-378, 75-378 and 80-378.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 2 (an Aspergillus niger asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 2; or is a fragment of SEQ ID NO: 2 which has asparaginase activity. Fragments of SEQ ID NO: 2 include the sequence of amino acids 80-378.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 3 (an Aspergillus fumigatus asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 3; or is a fragment of SEQ ID NO: 3 which has asparaginase activity. Fragments of SEQ ID NO: 3 include the sequence of amino acids 80-374.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 4 (an Aspergillus nidulans asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 4; or is a fragment of SEQ ID NO: 4 which has asparaginase activity. Fragments of SEQ ID NO: 4 include the sequence of amino acids 80-378.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 5 (a Penicillium citrinum asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 5; or is a fragment of SEQ ID NO: 5 which has asparaginase activity. Fragments of SEQ ID NO: 5 include the sequence of amino acids 80-379.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 6 (an Aspergillus terreus asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 6; or is a fragment of SEQ ID NO: 6 which has asparaginase activity. Fragments of SEQ ID NO: 6 include the sequence of amino acids 80-375.

In another embodiment, the asparaginase has at least 70% sequence identity to SEQ ID NO: 7 (a Pyrococcus furiosus asparaginase), e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the asparaginase comprises or consists of the sequence of SEQ ID NO: 7; or is a fragment of SEQ ID NO: 7 which has asparaginase activity. Fragments of SEQ ID NO: 7 include the sequence of amino acids 80-375.

An asparaginase useful according to the present invention may have the amino acid sequence disclosed in WO 2004/026043, WO 2004/030468, WO 2004/032648, WO 2008/110513, WO 2008/128974, WO 2008/128975, and WO 2008/151807, or an amino acid sequence having at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity to an asparaginase disclosed therein. Such an asparaginase is preferably derived from Aspergillus niger or Aspergillus oryzae.

Examples of asparaginases include variants of the above-listed asparaginases, e.g., variants, which have one or more conservative amino acid substitutions.

The asparaginase may be partly or completely post-translationally processed. For instance, they may be N-terminally truncated at different positions, so that different N-terminal sequences will be found. The wild-type Aspergillus oryzae asparaginase (SEQ ID NO: 1), when produced in Aspergillus oryzae, has been found to be heterogeneously processed such that at least four N-terminal sequences were found in a purified sample, corresponding to polypeptides being truncated to amino acids 27-378, 30-378, 75-378 or 80-378. Other asparaginases may be truncated at corresponding positions, or at other positions. For example, an asparaginase may be truncated immediately before the position corresponding to any of positions 27, 30, 75 or 80 of SEQ ID NO: 1. The term ‘immediately before’ means that the truncation takes place at the N-terminal side of the position mentioned.

The asparaginase may show a high thermotolerance, e.g., a high thermostability or a high relative asparaginase activity at a high temperature.

In one aspect, the asparaginase may be thermostable or have a high thermostability. The thermostability may be determined as the residual asparaginase activity after heat treatment divided by the asparaginase activity without heat treatment. Heat treatment may be incubation at pH 6 or around pH 6 at a high temperature for, e.g., 10, 20, 30 or 40 minutes. The asparaginase activity without heat treatment may be determined as the asparaginase activity of a sample which has been incubated at 4° C. in the same buffer and for the same time as the sample which is heat treated, or it may be the asparaginase activity before heat treatment.

The asparaginase may be thermostable and show a residual asparaginase activity of at least 90%, such as at least 80%, at least 70%, at least 60%, at least 50% or at least 40%, after incubation at pH 6 at a high temperature for a period of time, e.g., 20 minutes, compared to the asparaginase activity without heat treatment.

A high temperature in the context of the present invention may mean, e.g., 55° C., 58° C., 60° C., 61° C., 62° C., 63° C., 64° C., 65° C., 66° C., 67° C., 68° C., 69° C., 70° C., 72° C. or 75° C.

Asparaginase activity may be determined by any method known in the art. For example, asparaginase activity may be determined by incubating the enzyme with L-asparagine and hydroxylamine in a potassium phosphate buffer at pH 6 for 20 minutes followed by the coupling reaction with FeCl₂ and measuring A490, as described in Example 4 of WO 2008/135547. Incubation may be at any suitable temperature, e.g., 55° C.

In another aspect, the asparaginase may have a high relative activity at a high temperature compared to a reference temperature, e.g., 37° C., 40° C., 45° C. or 50° C. The asparaginase activity at a high temperature and, e.g., 37° C. may be determined as described above, where the incubation with asparagine is performed at a high temperature and 37° C., respectively. The asparaginase activity at a high temperature divided by the activity at 37° C. may be at least 110%, preferably at least 120%, such as at least 125%, 130%, 140%, 150%, 170% or 200%, more preferably at least 250%, such as at least 300%, and even more preferably at least 500% or at least 700%.

The asparaginase may be a variant, which comprises an amino acid difference in at least one of the following regions: positions 68-74, positions 279-288, positions 309-319, positions 329-342, and/or positions 356-363; wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1.

Thus, the asparaginase may comprise a difference in the amino acid sequence at one or more positions selected from the group consisting of 68, 69, 70, 71, 72, 73, 74, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 356, 357, 358, 359, 360, 361, 362, and/or 363, wherein each position corresponds to a position in SEQ ID NO: 1. In a preferred embodiment, the amino acid difference is a substitution.

In another embodiment, the asparaginase comprises an amino acid difference at one or more positions selected from the group consisting of D88, D111, K194, R196, D206, E235, E255, R266, D275, K290, E311, and E331; wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1. Preferably, the amino acid difference is a substitution. Therefore, in a preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of D88N, D111N, K194E, R196E, D206N, E235Q, E255Q, R266L, D275N, K290E, E311K, and E331Q.

In another embodiment, the asparaginase comprises an amino acid difference in at least one of the following positions selected from the group consisting of N70, G82, I83, Q84, T85, T113, D115, A137, V164, L201, N278, T280, F306, 1365, and E366, wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1. Preferably, the amino acid difference is a substitution. Therefore, in a preferred aspect, the asparaginase comprises at least one of the following amino acid substitutions selected from the group consisting of N70P, G82P, 183P, Q84P, T85P, T113P, D115P, A137P, V164P, L201P, N278P, T280P, F306P, 1365P, and E366P.

In another embodiment, the asparaginase comprises an amino acid difference in one or more of positions selected from the group consisting of S176, D223, G231, P246, Y271, S283, G328 (substitution to C will potentially result in formation of one or more disulfide bridges); D223, K249, and D286 (based on hydrophobic or electrostatic contacts), wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1. Preferably, the amino acid difference is a substitution. Therefore, in a preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of S176C; D223C; D223N/L; G231C; P246C; K249V/I/L; Y271C; S283C; D286R/N/L; and G328C.

In another embodiment, the asparaginase comprises an amino acid difference in one or more positions D69; N70; A72; N278; D279; T280; L281; S283; D286; K290; S307; E311; D312; H317; A336; E337; Q361; and K363, wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1. Preferably, the amino acid difference is a substitution. Therefore, in a preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of D69R/K; N70P/R/K; A72R/K; N278H/Q/R/K; D279N/V/R; T280D/E; L281 D/E; D286N/V/R; K290E/L; S307A/D/E; E311Q/I/R; D312Y/N/V/R; H317D/E; A336P; E337Q/R/K/I; Q361K/R; and K363P/Q/E/L.

In another embodiment, the asparaginase comprises an amino acid difference in one or more positions selected from the group consisting of 54, 57, 70, 83, 84, 86, 93-96, 102, 107, 137, 139, 165, 172, 184-186, 209, 212, 214, 215, 219, 220, 224, 260, 262, 264, 266, 299, 318, 320, 321, 323, 325, 327, 349, 351, 353 and 356, wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1. Preferably, the amino acid difference is a substitution. Therefore, in a preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of V54I, F57L, N70K, 183V, Q84D, L86P, M93L, L94K, N95D, V96L, V102D, V107I, A137I, V139I, I165L, S172A, L184Y, Q185N, S186A, V209G, F212R, A214V, S215T, A219T, N220T, T224A, N260K, T262D, I264L, R266K, S299N, N318G, P320V, I321V, A323R, T325S, T327V, A349Q, S351A, V353I and G356M.

In a more preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of V54I, F57L, N70K, I83V, Q84D, L86P, V102D, N260K, T262D, A323R, T327V, A349Q, S351A and V353I, wherein each position corresponds to a position in SEQ ID NO: 1.

In an even more preferred aspect, the asparaginase comprises one or more substitutions selected from the group consisting of N70K, A323R, T327V, A349Q, S351A and V353I, wherein each position corresponds to a position in SEQ ID NO: 1.

In another embodiment, the asparaginase comprises an amino acid difference in at least one of the following positions: 54, 57, 68-74, 82-86, 88, 93-96, 102, 107, 111, 113, 115, 137, 139, 164, 165, 172, 176, 184-186, 194, 196, 201, 206, 209, 212, 214, 215, 219, 220, 223, 224, 226, 228, 231, 235, 246, 249, 255, 260, 262, 264, 266, 271, 275, 278-288, 290, 299, 306, 307, 309-321, 323, 325, 327-342, 349, 351, 353, 356-363, 365, 366 and 375, wherein each position corresponds to a position in SEQ ID NO: 1.

Preferably, the asparaginase comprises an amino acid difference in at least one of the following positions: 54, 57, 70, 83, 84, 86, 102, 137, 164, 196, 201, 228, 260, 262, 278, 283, 290, 307, 312, 323, 327, 334, 336, 337, 349, 351, 353, 366 and/or 375, wherein each position corresponds to a position in SEQ ID NO: 1.

The asparaginase may comprise an amino acid substitution. Preferably, the asparaginase comprises at least one of the following substitutions: 54I, 57L, 69K/R, 70H/K/P/R/S, 72K/R, 82P, 83P/V, 84P/D, 85P, 86P, 88N, 93L, 94K, 95D, 96L, 102D, 107I, 111N, 113P, 115P, 137P/S/I, 139I, 164D/P, 165L, 172A, 176C, 184Y, 185N, 186A, 194E, 196E/I, 201P/Q, 206N, 209G, 212R, 214V, 215T, 219T, 220T, 223C/L/N, 224A, 228V, 231C, 235Q, 246C, 249I/L/V, 255Q, 260K, 262D, 264L, 266L/K, 2710, 275N, 278H/K/P/Q/R, 279N/R/V, 280D/E/P, 281D/E, 283C, 286L/N/R/V, 290E/L/V, 299N, 306P, 307A/D/E, 311I/K/Q/R, 312N/R/V/Y, 317D/E, 318G, 320V, 321V, 323R, 325S, 327V, 328C, 331Q, 334F, 336C/G/L/P, 337F/I/K/Q/R, 349Q, 351A, 353I, 356M, 361K/R, 363E/L/P/Q, 365P, 366P and/or 375T. More preferably, the asparaginase comprises at least one of the following substitutions: 54I, 57L, 70H/K/S, 83V, 84D, 86P, 102D, 137S, 164D, 196I, 201Q, 228V, 260K, 262D, 278H/Q, 283C, 290V, 307A, 312Y, 323R, 327V, 334F, 336C/G/L, 337F/I, 349Q, 351A, 353I, 366P and/or 375T. Even more preferably, the asparaginase comprises at least one, such as at least two, at least three, at least four or at least five, of the following substitutions: 70K, 323R, 327V, 349Q, 351A and/or 353I. Even more preferably, the asparaginase comprises the following substitutions: 70K, 323R, 327V, 349Q, 351A and 353I. Most preferably, the asparaginase has the same sequence as SEQ ID NO: 1, or a homologous sequence, except for the following substitutions: 70K, 323R, 327V, 349Q, 351A and 353I. The asparaginase may be a variant of a parent enzyme having the sequence of SEQ ID NO: 1 or a homologous sequence.

In one aspect, the asparaginase comprises an amino acid difference at a position corresponding to any of positions 70, 137, 164, 196, 201, 228, 278, 290, 366 and/or 375 in SEQ ID NO: 1. Preferably, the asparaginase comprises at least one of the following substitutions: 70H/K/S, 137S, 164D, 1961, 201Q, 228V, 278H/Q, 290V, 366P and/or 375T. The asparaginase may have a high relative asparaginase activity at high temperature.

Particularly preferred asparaginases comprise the following substitutions or sets of substitutions: 70H, 70K, 70K+278H, 70K+278H+196I, 70K+278H+201Q, 70K+283C, 70S, 137S, 137S+228V, 164D, 196I, 201Q, 278H, 278Q, 290V, 366P, and/or 366P+375T.

In another preferred aspect, the asparaginase comprises an amino acid difference in at least one of the following positions: 70, 283, 307, 312, 334, 336 and/or 337. Preferably, the asparaginase comprises at least one of the following substitutions: 70K, 283C, 307A, 312Y, 334F, 336C/G/L and/or 337F/I, wherein each position corresponds to a position of amino acids 1 to 378 of SEQ ID NO: 1.

Particularly preferred asparaginases comprise the following substitutions or sets of substitutions: 70K, 70K+283C, 70K+283C+307A+312Y, 70K+283C+307A+312Y+336L+337F, 70K+307A, 70K+307A+312Y, 70K+307A+312Y+334F, 70K+307A+312Y+336G+337I, 70K+307A+312Y+336L+337F, 70K+312Y, and/or 70K+336C+337F.

In another preferred aspect of the present invention, the asparaginase comprises an amino acid difference at a position corresponding to any of positions 54, 57, 70, 83, 84, 86, 93-96, 102, 107, 137, 139, 165, 172, 184-186, 209, 212, 214, 215, 219, 220, 224, 260, 262, 264, 266, 299, 318, 320, 321, 323, 325, 327, 349, 351, 353 and/or 356 in SEQ ID NO: 1. Preferably, the asparaginase comprises at least one of the following substitutions: V54I, F57L, N70K, 183V, Q84D, L86P, M93L, L94K, N95D, V96L, V102D, V107I, A1371, V139I, I165L, S172A, L184Y, Q185N, S186A, V209G, F212R, A214V, S215T, A219T, N220T, T224A, N260K, T262D, I264L, R266K, S299N, N318G, P320V, I321V, A323R, T325S, T327V, A349Q, S351A, V353I and/or G356M. More preferably, the asparaginase comprises at least one of the following substitutions: V54I, F57L, N70K, I83V, Q84D, L86P, V102D, N260K, T262D, A323R, T327V, A349Q, S351A and/or V353I. Most preferably, the asparaginase comprises at least one, such as at least two, at least three, at least four or at least five, of the following substitutions: N70K, A323R, T327V, A349Q, S351A and/or V353I. The asparaginase may have a high relative asparaginase activity at a high temperature.

Particularly preferred asparaginases comprise the following sets of substitutions: N70K+V54I+F57L, N70K+I83V+Q84D+A323R+T327V, N70K+183V+Q84D+A323R+T327V+A349Q+S351A+V353I, N70K+L86P+V102D+A323R+T327V, N70K+V102D+A323R+T327V+A349Q+S351A+V353I, N70K+N260K+T262D, N70K+A323R+T327V, N70K+A323R+T327V+A349Q+S351A+V353I, and/or N70K+A349Q+S351A+V353I.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 1.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 2.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 3.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 4.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 5.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 6.

In an embodiment, an asparaginase variant has at least 70% sequence identity e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99%, but less than 100% sequence identity to SEQ ID NO: 7.

An asparaginase may be a tetramer in its most active form.

In one embodiment, the asparaginase is provided in an amount of about 100-10,000 ASNU per kg dry matter, more preferably about 250-8,000 ASNU per kg dry matter, more preferably about 500-7,500 ASNU per kg dry matter and most preferably about 1,000-5,000 ASNU per kg dry matter.

An asparaginase unit (ASNU) is defined as the amount of enzyme needed to generate 1.0 micromole of ammonia from hydrolyzing asparagine in 1 minute at 37° C. and pH 7.0. The concentration of asparagine when determining the activity may be 9.6 mg/ml.

Amino Acid Oxidases

Amino acid oxidases, belonging to enzyme classes EC1.4.3.2 and EC1.4.3.3, are oxidoreductases which catalyze the deamination of amino acids found in nature to the corresponding oxo-acids. An amino acid oxidase from fungal, bacterial, or plant sources may be used. The amino acid oxidase may, e.g., be derived from Bothrops atrox, Rhodococcus opacus, Trichoderma harzianum, Trigonopsis variabilis, or another organism.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 8, a Bothrops atrox amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 8; or is a fragment of SEQ ID NO: 8 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 9, a Trichoderma harzianum amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 9; or is a fragment of SEQ ID NO: 9 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 10, a Trigonopsis variabilis amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 10; or is a fragment of SEQ ID NO: 10 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 11, a Rhodococcus opacus amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 11; or is a fragment of SEQ ID NO: 11 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 12, an Aspergillus nidulans amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 12; or is a fragment of SEQ ID NO: 12 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 13, a Streptococcus oligofermentans amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 13; or is a fragment of SEQ ID NO: 13 which has amino acid oxidase activity.

In another embodiment, the amino acid oxidase has at least 70% sequence identity to SEQ ID NO: 14, a Neurospora crassa amino acid oxidase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the amino acid oxidase comprises or consists of the sequence of SEQ ID NO: 14; or is a fragment of SEQ ID NO: 14 which has amino acid oxidase activity.

An amino acid oxidase useful according to the present invention may have the amino acid sequence disclosed in WO 94/25574; WO 2005/098000; EP 1205542; Alves et al., 2008, UniProt Database, Accession No. P0CC17; Davis et al., 2005, Appl. Environ. Microbiol. 71(7): 3551-3555; Tong et al., 2008, J. Bacteriol. 190(13): 4716-4721; Niedermann et al., 1990, J. Biol. Chem. 265(28): 17246-17251; or an amino acid sequence having at least 50%, at least 60%, at least 70%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identity to an amino acid oxidase disclosed therein.

Arginases

Arginases (L-Arginine aminohydrolase, EC 3.5.3.1) are a group of enzymes which catalyze the hydrolysis of arginine to ornithine and urea. An arginase from fungal, bacterial, plant, or animal sources may be used.

In an embodiment, the arginase has at least 70% sequence identity to SEQ ID NO: 15, a Bacillus cereus arginase, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the arginase comprises or consists of the sequence of SEQ ID NO: 15; or is a fragment of SEQ ID NO: 15 which has arginase activity.

In another embodiment, the arginase has at least 70% sequence identity to SEQ ID NO: 16, an arginase obtained from tomato, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the arginase comprises or consists of the sequence of SEQ ID NO: 16; or is a fragment of SEQ ID NO: 16 which has arginase activity.

In another embodiment, the arginase has at least 70% sequence identity to SEQ ID NO: 17, an arginase obtained from mushroom, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the arginase comprises or consists of the sequence of SEQ ID NO: 17; or is a fragment of SEQ ID NO: 17 which has arginase activity.

In another embodiment, the arginase has at least 70% sequence identity to SEQ ID NO: 18, an arginase from pig, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the arginase comprises or consists of the sequence of SEQ ID NO: 18; or is a fragment of SEQ ID NO: 18 which has arginase activity.

In another embodiment, the arginase has at least 70% sequence identity to SEQ ID NO: 19, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity. In another embodiment, the arginase comprises or consists of the sequence of SEQ ID NO: 19; or is a fragment of SEQ ID NO: 19 which has arginase activity.

According to the invention arginase and asparginase are equivalent enzymes due to the similar mode of action. Both enzymes (i.e., arginase and asparginase) act on the nitrogen-containing side chains of similar amino acids and release nitrogen-containing compounds, i.e., release urea (CO(NH₂)₂) and amonia (NH₃), respectively.

Alpha-Amylases

According to the invention any alpha-amylase may be used, such as of fungal, bacterial or plant origin. In a preferred embodiment the alpha-amylase is an acid alpha-amylase, e.g., acid fungal or acid bacterial alpha-amylase. The term “acid alpha-amylase” means an alpha-amylase (EC 3.2.1.1) which added in an effective amount has activity optimum at a pH in the range of 3 to 7, preferably from 3.5 to 6, or more preferably from 4-5.

Bacterial Alpha-Amylases

An alpha-amylase for use in the present invention may be a bacterial alpha-amylase, e.g., derived from Bacillus. In a preferred embodiment the Bacillus alpha-amylase is derived from a strain of Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus stearothermophilus, or Bacillus subtilis, but may also be derived from other Bacillus sp.

Specific examples of alpha-amylases include the Bacillus amyloliquefaciens alpha-amylase of SEQ ID NO: 5 in WO 99/19467, the Bacillus licheniformis alpha-amylase of SEQ ID NO: 4 in WO 99/19467, and the Bacillus stearothermophilus alpha-amylase of SEQ ID NO: 3 in WO 99/19467 (all sequences are hereby incorporated by reference). In an embodiment the alpha-amylase may be an enzyme having a degree of identity of at least 60%, e.g., at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% to any of the sequences shown in SEQ ID NOS: 3, 4 or 5, respectively, in WO 99/19467.

The Bacillus alpha-amylase may also be a variant and/or hybrid, especially one described in any of WO 96/23873, WO 96/23874, WO 97/41213, WO 99/19467, WO 00/60059, and WO 02/10355 (all documents are hereby incorporated by reference). Specific alpha-amylase variants are disclosed in U.S. Pat. Nos. 6,093,562, 6,187,576, and 6,297,038 (hereby incorporated by reference) and include Bacillus stearothermophilus alpha-amylase (BSG alpha-amylase) variants having a deletion of one or two amino acids at positions R179 to G182, preferably a double deletion disclosed in WO 96/23873—see, e.g., page 20, lines 1-10 (hereby incorporated by reference), preferably corresponding to delta (181-182) compared to the amino acid sequence of Bacillus stearothermophilus alpha-amylase set forth in SEQ ID NO: 3 disclosed in WO 99/19467 or the deletion of amino acids R179 and G180 using SEQ ID NO: 3 in WO 99/19467 for numbering (which reference is hereby incorporated by reference). Even more preferred are Bacillus alpha-amylases, especially Bacillus stearothermophilus alpha-amylases, which have a double deletion corresponding to delta (181-182) and further comprise a N193F substitution (also denoted I181*+G182*+N193F) compared to the wild-type BSG alpha-amylase amino acid sequence set forth in SEQ ID NO: 3 disclosed in WO 99/19467.

Bacterial Hybrid Alpha-Amylases

The alpha-amylase may be a hybrid alpha-amylase, e.g., an alpha-amylase comprising 445 C-terminal amino acid residues of the Bacillus licheniformis alpha-amylase (shown in SEQ ID NO: 4 of WO 99/19467) and the 37 N-terminal amino acid residues of the alpha-amylase derived from Bacillus amyloliquefaciens (shown in SEQ ID NO: 5 of WO 99/19467), with one or more, especially all, of the following substitutions: G48A+T49I+G107A+H156Y+A181T+N190F+I201F+A209V+Q264S (using the Bacillus licheniformis numbering in SEQ ID NO: 4 of WO 99/19467). Also preferred are variants having one or more of the following mutations (or corresponding mutations in other Bacillus alpha-amylases): H154Y, A181T, N190F, A209V and Q264S and/or the deletion of two residues between positions 176 and 179, preferably the deletion of E178 and G179 (using SEQ ID NO: 5 of WO 99/19467 for position numbering).

In an embodiment, the bacterial alpha-amylase is dosed in an amount of 0.0005-5 KNU per g DS (dry solids), preferably 0.001-1 KNU per g DS, such as around 0.050 KNU per g DS.

Fungal Alpha-Amylases

Fungal alpha-amylases include alpha-amylases derived from a strain of Aspergillus, such as, Aspergillus kawachii, Aspergillus niger and Aspergillus oryzae alpha-amylases.

A preferred acidic fungal alpha-amylase is an alpha-amylase which exhibits a high identity, i.e., at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or even 100% identity to the mature part of the amino acid sequence shown in SEQ ID NO: 10 in WO 96/23874.

Another preferred acid alpha-amylase is derived from a strain of Aspergillus niger. In a preferred embodiment the acid fungal alpha-amylase is an Aspergillus niger alpha-amylase disclosed as “AMYA_ASPNG” in the Swiss-prot/TeEMBL database under the primary accession no. P56271 and described in WO 89/01969 (Example 3—incorporated by reference). A commercially available acid fungal alpha-amylase derived from Aspergillus niger is SP288 (available from Novozymes A/S, Denmark).

Other wild-type alpha-amylases include those derived from a strain of Meripilus and Rhizomucor, preferably a strain of Meripilus giganteus or Rhizomucor pusillus (WO 2004/055178 which is incorporated herein by reference).

In a preferred embodiment the alpha-amylase is derived from Aspergillus kawachii (Kaneko et al., 1996, J. Ferment. Bioeng. 81: 292-298, “Molecular-cloning and determination of the nucleotide-sequence of a gene encoding an acid-stable alpha-amylase from Aspergillus kawachii”; and further as EMBL: #AB008370).

The fungal alpha-amylase may also be a wild-type enzyme comprising a starch-binding domain (SBD) and an alpha-amylase catalytic domain, or a variant thereof.

Fungal Hybrid Alpha-Amylases

In a preferred embodiment the fungal acid alpha-amylase is a hybrid alpha-amylase. Examples of fungal hybrid alpha-amylases include the ones disclosed in WO 2005/003311, U.S. Patent Application Publication No. 2005/0054071 (Novozymes), and WO 2006/069290 (Novozymes), which are hereby incorporated by reference. A hybrid alpha-amylase may comprise an alpha-amylase catalytic domain (CD) and a carbohydrate-binding domain/module (CBM), such as a starch binding domain (SBD), and optionally a linker.

Examples of hybrid alpha-amylases include those disclosed in Tables 1 to 5 of the examples in WO 2006/069290 including the variant with the catalytic domain JA118 and Athelia rolfsii SBD (SEQ ID NO: 100 in WO 2006/069290), Rhizomucor pusillus alpha-amylase with Athelia rolfsii AMG linker and SBD (SEQ ID NO: 101 in WO 2006/069290), Rhizomucor pusillus alpha-amylase with Aspergillus niger glucoamylase linker and SBD (which is disclosed in Table 5 as a combination of amino acid sequences SEQ ID NO: 20, SEQ ID NO: 72 and SEQ ID NO: 96 in U.S. application Ser. No. 11/316,535) or as V039 in Table 5 in WO 2006/069290, and Meripilus giganteus alpha-amylase with Athelia rolfsii glucoamylase linker and SBD (SEQ ID NO: 102 in WO 2006/069290). Other hybrid alpha-amylases are listed in Tables 3, 4, 5, and 6 in Example 4 in U.S. application Ser. No. 11/316,535 and WO 2006/069290 (which are hereby incorporated by reference).

Other examples of hybrid alpha-amylases include those disclosed in U.S. Patent Application Publication No. 2005/0054071, including those disclosed in Table 3 on page 15, such as Aspergillus niger alpha-amylase with Aspergillus kawachii linker and starch binding domain.

Other alpha-amylases exhibit a high degree of sequence identity to any of above mentioned alpha-amylases, i.e., at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or even 100% identity to the mature enzyme sequences disclosed above.

An acid alpha-amylase may according to the invention be added in an amount of 0.001 to 10 AFAU/g DS, preferably from 0.01 to 5 AFAU/g DS, especially 0.3 to 2 AFAU/g DS or 0.001 to 1 FAU-F/g DS, preferably 0.01 to 1 FAU-F/g DS.

Commercial Alpha-Amylase Products

Preferred commercial compositions comprising alpha-amylase include MYCOLASE™ (DSM), BAN™, TERMAMYL™ SC, FUNGAMYL™, LIQUOZYME™ X, LIQUOZYME™ SC and SAN™ SUPER, SAN™ EXTRA L (Novozymes A/S) and CLARASE™ L-40,000, DEX-LO™, SPEZYME™ FRED, SPEZYME™ AA, SPEZYME™ ALPHA, SPEZYME™ DELTA AA, GC358, GC980, SPEZYME™ CL and SPEZYME™ RSL (Danisco A/S), and the acid fungal alpha-amylase from Aspergillus niger referred to as SP288 (available from Novozymes A/S, Denmark).

Carbohydrate-Source Generating Enzymes (Saccharifying Enzymes)

The term “carbohydrate-source generating enzyme” includes glucoamylase (a glucose generator), beta-amylase and maltogenic amylase (both maltose generators) and also alpha-glucosidase, isoamylase and pullulanase. A carbohydrate-source generating enzyme is capable of producing a carbohydrate that can be used as an energy-source by the fermenting organism(s) in question, for instance, when used in a process of the invention for producing a fermentation product, such as ethanol. The generated carbohydrate may be converted directly or indirectly to the desired fermentation product, preferably ethanol. According to the invention a mixture of carbohydrate-source generating enzymes may be used. Blends include mixtures comprising at least a glucoamylase and an alpha-amylase, especially an acid amylase, even more preferred an acid fungal alpha-amylase.

The ratio between glucoamylase activity (AGU) and acid fungal alpha-amylase activity (FAU-F) (i.e., AGU per FAU-F) may in a preferred embodiment of the invention be between 0.1 and 100 AGU/FAU-F, in particular between 2 and 50 AGU/FAU-F, such as in the range from 10-40 AGU/FAU-F, especially when performing a one-step fermentation (raw starch hydrolysis—RSH), i.e., when saccharification and fermentation are carried out simultaneously (i.e., without a liquefaction step).

In a conventional starch-to-ethanol process (i.e., including a liquefaction step) the ratio may preferably be as defined in EP 140410, especially when saccharification and fermentation are carried out simultaneously.

Glucoamylases

A glucoamylase may be derived from any suitable source, e.g., derived from a microorganism or a plant. Preferred glucoamylases are of fungal or bacterial origin, selected from the group consisting of Aspergillus glucoamylases, in particular Aspergillus niger G1 or G2 glucoamylase (Boel et al., 1984, EMBO J. 3(5): 1097-1102), or variants thereof, such as those disclosed in WO 92/00381, WO 00/04136 and WO 01/04273 (from Novozymes, Denmark); the A. awamori glucoamylase disclosed in WO 84/02921, Aspergillus oryzae glucoamylase (Hata et al., 1991, Agric. Biol. Chem. 55(4): 941-949), or variants or fragments thereof. Other Aspergillus glucoamylase variants include variants with enhanced thermal stability: G137A and G139A (Chen et al., 1996, Prot. Eng. 9: 499-505); D257E and D293E/Q (Chen et al., 1995, Prot. Eng. 8: 575-582); N182 (Chen et al., 1994, Biochem. J. 301: 275-281); disulphide bonds, A246C (Fierobe et al., 1996, Biochemistry 35: 8698-8704; and introduction of Pro residues in positions A435 and S436 (Li et al., 1997, Protein Eng. 10: 1199-1204.

Other glucoamylases include Athelia rolfsii (previously denoted Corticium rolfsii) glucoamylase (see U.S. Pat. No. 4,727,026 and Nagasaka et al., 1998, Appl. Microbiol. Biotechnol. 50: 323-330), Talaromyces glucoamylases, in particular derived from Talaromyces duponti, Talaromyces emersonii (WO 99/28448), Talaromyces leycettanus (U.S. Pat. No. Re. 32,153), and Talaromyces thermophilus (U.S. Pat. No. 4,587,215).

Bacterial glucoamylases include glucoamylases from Clostridium, in particular C. thermoamylolyticum (EP 135138) and C. thermohydrosulfuricum (WO 86/01831), Trametes cingulata, Pachykytospora papyracea, and Leucopaxillus giganteus, all disclosed in WO 2006/069289; or Peniophora rufomarginata disclosed in PCT/US2007/066618; or a mixture thereof. A hybrid glucoamylase may be used in the present invention. Examples of hybrid glucoamylases are disclosed in WO 2005/045018. Specific examples include the hybrid glucoamylase disclosed in Tables 1 and 4 of Example 1 (which hybrids are hereby incorporated by reference).

The glucoamylase may have a high degree of sequence identity to any of above mentioned glucoamylases, i.e., at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or even 100% identity to the mature enzymes sequences mentioned above.

Commercially available glucoamylase compositions include AMG 200L; AMG 300L; SAN™ SUPER, SAN™ EXTRA L, SPIRIZYME™ PLUS, SPIRIZYME™ FUEL, SPIRIZYME™ B4U, SPIRIZYME ULTRA™ and AMG™ E (from Novozymes A/S, Denmark); OPTIDEX™ 300, GC480™ and GC147™ (from Genencor Int., USA); AMIGASE™ and AMIGASE™ PLUS (from DSM); G-ZYME™ G900, G-ZYME™ and G990 ZR (from Genencor Int.).

Glucoamylases may be added in an amount of 0.02-20 AGU/g DS, preferably 0.1-10 AGU/g DS, especially between 1-5 AGU/g DS, such as 0.1-2 AGU/g DS, such as 0.5 AGU/g DS or in an amount of 0.0001-20 AGU/g DS, preferably 0.001-10 AGU/g DS, especially between 0.01-5 AGU/g DS, such as 0.1-2 AGU/g DS.

Beta-amylases

A beta-amylase (E.C 3.2.1.2) is the name traditionally given to exo-acting maltogenic amylases, which catalyze the hydrolysis of 1,4-alpha-glucosidic linkages in amylose, amylopectin and related glucose polymers. Maltose units are successively removed from the non-reducing chain ends in a step-wise manner until the molecule is degraded or, in the case of amylopectin, until a branch point is reached. The maltose released has the beta anomeric configuration, hence the name beta-amylase.

Beta-amylases have been isolated from various plants and microorganisms (Fogarty and Kelly, 1979, Progress in Industrial Microbiology 15: 112-115). These beta-amylases are characterized by having a temperature optimum in the range from 40° C. to 65° C. and a pH optimum in the range from 4.5 to 7. A commercially available beta-amylase from barley is NOVOZYM™ WBA from Novozymes A/S, Denmark and SPEZYME™ BBA 1500 from Genencor Int., USA.

Maltogenic Amylases

The amylase may also be a maltogenic alpha-amylase (glucan 1,4-alpha-maltohydrolase, EC 3.2.1.133), which catalyzes the hydrolysis of amylose and amylopectin to maltose in the alpha-configuration. A maltogenic amylase from Bacillus stearothermophilus strain NCIB 11837 is commercially available from Novozymes A/S. Maltogenic alpha-amylases are described in U.S. Pat. Nos. 4,598,048, 4,604,355 and 6,162,628, which are hereby incorporated by reference.

The maltogenic amylase may be added in an amount of 0.05-5 mg total protein/gram DS or 0.05-5 MANU/g DS.

Phytases

Any phytase may be used in a process of the present invention. Phytases are enzymes that degrade phytates and/or phytic acid by specifically hydrolyzing the ester link between inositol and phosphorus. Phytase activity is credited with phosphorus and ion availability in many ingredients. In some embodiments, the phytase is capable of liberating at least one inorganic phosphate from an inositol hexaphosphate (e.g., phytic acid). Phytases can be grouped according to their preference for a specific position of the phosphate ester group on the phytate molecule at which hydrolysis is initiated (e.g., 3-phytase (EC 3.1.3.8) or 6-phytase (EC 3.1.3.26)). An example of phytase is myo-inositol-hexakiphosphate-3-phosphohydrolase.

Phytases can be obtained from microorganisms such as fungal and bacterial organisms. For example, the phytase may be obtained from filamentous fungi such as Aspergillus (e.g., A. ficuum, A. fumigatus, A. niger, and A. terreus), Cladospirum, Mucor (e.g., Mucor piriformis), Myceliophthora (e.g., M. thermophila), Penicillium (e.g., P. hordei (ATCC No. 22053)), P. piceum (ATCC No. 10519), or P. brevi-compactum (ATCC No. 48944), Talaromyces (e.g., T. thermophilus), Thermomyces (WO 99/49740), and Trichoderma spp. (e.g., T. reesei).

In an embodiment, the phytate-degrading enzyme is obtained from yeast (e.g., Arxula adeninivorans, Pichia anomala, Schwanniomyces occidentalis), gram-negative bacteria (e.g., Escherichia coli, Klebsiella spp., Pseudomonas spp.), and gram-positive bacteria (e.g., Bacillus spp. such as Bacillus subtilis).

The phytase also may be obtained from Citrobacter, Enterbacter, or Peniophora.

In an embodiment, the phytase is derived from Buttiauxiella spp. such as B. agrestis, B. brennerae, B. ferragutiase, B. gaviniae, B. izardii, B. noackiae, and B. warmboldiae. In some embodiments, the phytase is a phytase disclosed in WO 2006/043178 or U.S. application Ser. No. 11/714,487.

In one preferred embodiment, the phytase has at least 75%, at least 80%, at least 85%, at least 88%, at least 90%, at least 93%, at least 95%, at least 96%, at least 97%, at least 98% and at least 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 31 of U.S. application Ser. No. 12/263,886.

Commercially-available phytases are NATUPHOS (BASF), RONOZYME P (Novozymes A/S), PHZYME (Danisco A/S, Diverse) and FINASE (AB Enzymes). The method for determining microbial phytase activity and the definition of a phytase unit is disclosed in Engelen et al., 1994, Journal of AOAC International 77: 760-764. The phytase may be a wild-type phytase, an active variant or active fragment thereof.

Pullulanases

Any pullulanase may be used in a process of the present invention. In an embodiment, the pullulanase is a GH57 pullulanase, e.g., a pullulanase obtained from a strain of Thermococcus, including Thermococcus sp. AM4, Thermococcus sp. HJ21, Thermococcus barophilus, Thermococcus gammatolerans, Thermococcus hydrothermalis; Thermococcus kodakarensis, Thermococcus litoralis, and Thermococcus onnurineus; or from a strain of Pyrococcus, such as Pyrococcus abyssi and Pyrococcus furiosus.

Proteases

A protease may be added during saccharification, fermentation, simultaneous saccharification and fermentation. The protease may be any protease. In a preferred embodiment the protease is an acid protease of microbial origin, preferably of fungal or bacterial origin. An acid fungal protease is preferred, but also other proteases can be used.

Suitable proteases include microbial proteases, such as fungal and bacterial proteases. Preferred proteases are acidic proteases, i.e., proteases characterized by the ability to hydrolyze proteins under acidic conditions below pH 7.

The acid fungal protease may be derived from Aspergillus, Candida, Coriolus, Endothia, Enthomophtra, Irpex, Mucor, Penicillium, Rhizopus, Sclerotium, and Torulopsis. In particular, the protease may be derived from Aspergillus aculeatus (WO 95/02044), Aspergillus awamori (Hayashida et al., 1977, Agric. Biol. Chem. 42(5), 927-933), Aspergillus niger (see, e.g., Koaze et al., 1964, Agr. Biol. Chem. Japan 28: 216), Aspergillus saitoi (see, e.g., Yoshida, 1954, J. Agr. Chem. Soc. Japan 28: 66), or Aspergillus oryzae, such as the pepA protease; and acidic proteases from Mucor miehei or Mucor pusiflus.

The protease may be a neutral or alkaline protease, such as a protease derived from a strain of Bacillus. A particular protease is derived from Bacillus amyloliquefaciens and has the sequence obtainable at Swissprot as Accession No. P06832. The proteases may have at least 90% sequence identity to the amino acid sequence disclosed in the Swissprot Database, Accession No. P06832 such as at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, or particularly at least 99% identity.

The protease may have at least 90% sequence identity to the amino acid sequence disclosed as SEQ ID NO: 1 in WO 2003/048353 such as at 92%, at least 95%, at least 96%, at least 97%, at least 98%, or particularly at least 99% identity.

The protease may be a papain-like protease selected from the group consisting of proteases within EC 3.4.22.* (cysteine protease), such as EC 3.4.22.2 (papain), EC 3.4.22.6 (chymopapain), EC 3.4.22.7 (asclepain), EC 3.4.22.14 (actinidain), EC 3.4.22.15 (cathepsin L), EC 3.4.22.25 (glycyl endopeptidase) and EC 3.4.22.30 (caricain).

In an embodiment, the protease is a protease preparation derived from a strain of Aspergillus, such as Aspergillus oryzae. In another embodiment the protease is derived from a strain of Rhizomucor, preferably Rhizomucor miehei. In another embodiment the protease is a protease preparation, preferably a mixture of a proteolytic preparation derived from a strain of Aspergillus, such as Aspergillus oryzae, and a protease derived from a strain of Rhizomucor, preferably Rhizomucor miehei.

Aspartic acid proteases are described in, for example, Handbook of Proteolytic Enzymes, Edited by A. J. Barrett, N. D. Rawlings and J. F. Woessner, Academic Press, San Diego, 1998, Chapter 270. Examples of aspartic acid proteases include, e.g., those disclosed in Berka et al., 1990, Gene 96: 313; Berka et al., 1993, Gene 125: 195-198; and Gomi et al., 1993, Biosci. Biotech. Biochem. 57: 1095-1100, which are hereby incorporated by reference.

The protease also may be a metalloprotease, which is defined as a protease selected from the group consisting of:

(a) proteases belonging to EC 3.4.24 (metalloendopeptidases); preferably EC 3.4.24.39 (acid metallo proteinases);

(b) metalloproteases belonging to the M group of the above Handbook;

(c) metalloproteases not yet assigned to clans (designation: Clan MX), or belonging to either one of clans MA, MB, MC, MD, ME, MF, MG, MH (as defined at pp. 989-991 of the above Handbook);

(d) other families of metalloproteases (as defined at pp. 1448-1452 of the above Handbook);

(e) metalloproteases with a HEXXH motif;

(f) metalloproteases with an HEFTH motif;

(g) metalloproteases belonging to either one of families M3, M26, M27, M32, M34, M35, M36, M41, M43, or M47 (as defined at pp. 1448-1452 of the above Handbook);

(h) metalloproteases belonging to the M28E family; and

(i) metalloproteases belonging to family M35 (as defined at pp. 1492-1495 of the above Handbook).

In other particular embodiments, metalloproteases are hydrolases in which the nucleophilic attack on a peptide bond is mediated by a water molecule, which is activated by a divalent metal cation. Examples of divalent cations are zinc, cobalt or manganese. The metal ion may be held in place by amino acid ligands. The number of ligands may be five, four, three, two, one or zero. In a particular embodiment the number is two or three, preferably three.

There are no limitations on the origin of the metalloprotease used in a process of the invention. In an embodiment the metalloprotease is classified as EC 3.4.24, preferably EC 3.4.24.39. In one embodiment, the metalloprotease is an acid-stable metalloprotease, e.g., a fungal acid-stable metalloprotease, such as a metalloprotease derived from a strain of the genus Thermoascus, preferably a strain of Thermoascus aurantiacus, especially Thermoascus aurantiacus CGMCC No. 0670 (classified as EC 3.4.24.39). In another embodiment, the metalloprotease is derived from a strain of the genus Aspergillus, preferably a strain of Aspergillus oryzae.

In one embodiment the metalloprotease has a degree of sequence identity to amino acids −178 to 177, −159 to 177, or preferably amino acids 1 to 177 (the mature polypeptide) of SEQ ID NO: 1 of WO 2010/008841 (a Thermoascus aurantiacus metalloprotease) of at least 80%, at least 82%, at least 85%, at least 90%, at least 95%, or at least 97%; and which have metalloprotease activity. In particular embodiments, the metalloprotease consists of an amino acid sequence with a degree of identity to SEQ ID NO: 1 as mentioned above.

The Thermoascus aurantiacus metalloprotease is a preferred example of a metalloprotease suitable for use in a process of the invention. Another metalloprotease is derived from Aspergillus oryzae and comprises the sequence of SEQ ID NO: 11 disclosed in WO 2003/048353, or amino acids −23-353; −23-374; −23-397; 1-353; 1-374; 1-397; 177-353; 177-374; or 177-397 thereof, and SEQ ID NO: 10 disclosed in WO 2003/048353.

Another metalloprotease suitable for use in a process of the invention is the Aspergillus oryzae metalloprotease comprising SEQ ID NO: 5 of WO 2010/008841, or a metalloprotease is an isolated polypeptide which has a degree of identity to SEQ ID NO: 5 of at least about 80%, at least 82%, at least 85%, at least 90%, at least 95%, or at least 97%; and which have metalloprotease activity. In particular embodiments, the metalloprotease consists of the amino acid sequence of SEQ ID NO: 5.

In a particular embodiment, a metalloprotease has an amino acid sequence that differs by forty, thirty-five, thirty, twenty-five, twenty, or by fifteen amino acids from amino acids −178 to 177, −159 to 177, or +1 to 177 of the amino acid sequences of the Thermoascus aurantiacus or Aspergillus oryzae metalloprotease.

In another embodiment, a metalloprotease has an amino acid sequence that differs by ten, or by nine, or by eight, or by seven, or by six, or by five amino acids from amino acids −178 to 177, −159 to 177, or +1 to 177 of the amino acid sequences of these metalloproteases, e.g., by four, by three, by two, or by one amino acid.

In particular embodiments, the metalloprotease a) comprises or b) consists of

i) the amino acid sequence of amino acids −178 to 177, −159 to 177, or +1 to 177 of SEQ ID NO:1 of WO 2010/008841;

ii) the amino acid sequence of amino acids −23-353, −23-374, −23-397, 1−353, 1-374, 1-397, 177-353, 177-374, or 177-397 of SEQ ID NO: 3 of WO 2010/008841;

iii) the amino acid sequence of SEQ ID NO: 5 of WO 2010/008841; or allelic variants, or fragments, of the sequences of i), ii), and iii) that have protease activity.

A fragment of amino acids −178 to 177, −159 to 177, or +1 to 177 of SEQ ID NO: 1 of WO 2010/008841 or of amino acids −23-353, −23-374, −23-397, 1-353, 1-374, 1-397, 177-353, 177-374, or 177-397 of SEQ ID NO: 3 of WO 2010/008841; is a polypeptide having one or more amino acids deleted from the amino and/or carboxyl terminus of these amino acid sequences. In one embodiment a fragment contains at least 75 amino acid residues, or at least 100 amino acid residues, or at least 125 amino acid residues, or at least 150 amino acid residues, or at least 160 amino acid residues, or at least 165 amino acid residues, or at least 170 amino acid residues, or at least 175 amino acid residues.

In another embodiment, the metalloprotease is combined with another protease, such as a fungal protease, preferably an acid fungal protease.

Commercially available products include ALCALASE®, ESPERASE™ FLAVOURZYME™, NEUTRASE®, RENNILASE®, NOVOZYM™ FM 2.0L, and iZyme BA (available from Novozymes A/S, Denmark) and GC106™ and SPEZYME™ FAN from Genencor International, Inc., USA.

The protease may be present in an amount of 0.0001-1 mg enzyme protein per g DS, preferably 0.001 to 0.1 mg enzyme protein per g DS. Alternatively, the protease may be present in an amount of 0.0001 to 1 LAPU/g DS, preferably 0.001 to 0.1 LAPU/g DS and/or 0.0001 to 1 mAU-RH/g DS, preferably 0.001 to 0.1 mAU-RH/g DS.

Compositions

In this aspect the invention relates to a composition comprising (a) an asparaginase and/or amino acid oxidase, (b) a glucoamylase and (c) an alpha-amylase.

In an embodiment the composition further comprises one or more other carbohydrases, such as alpha-amylases. In a preferred embodiment the alpha-amylase is an acid alpha-amylase or a fungal alpha-amylase, preferably an acid fungal alpha-amylase.

The composition may comprise one or more carbohydrate-source generating enzymes, such as especially glucoamylases, beta-amylases, maltogenic amylases, pullulanases, alpha-glucosidases, or a mixture thereof.

In another preferred embodiment the composition comprises one or more asparaginases and/or amino acid oxidases and one or more fermenting organisms, such as yeast and/or bacteria. Examples of fermenting organisms can be found in the “Fermenting Organism” section above.

Uses

The invention also relates to the use of asparaginase and/or amino acid oxidase in a fermentation process. In an embodiment an asparaginase and/or amino acid oxidase is used for improving the fermentation product yield. In another embodiment, an asparaginase and/or amino acid oxidase is used for increasing growth of the fermenting organism(s).

Modified Fermenting Organism

The invention also relates to a modified fermenting organism transformed with a polynucleotide encoding an asparaginase and/or amino acid oxidase, wherein the fermenting organism is capable of expressing the asparaginase and/or amino acid oxidase at fermentation conditions.

In a preferred embodiment the fermenting organism is a microbial organism, such as yeast or filamentous fungus, or a bacterium. Examples of other fermenting organisms can be found in the “Fermenting Organisms” section.

A fermenting organism may be transformed with a gene encoding an asparaginase and/or an amino acid oxidase using techniques well known in the art.

The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure, including definitions will be controlling.

Various references are cited herein, the disclosures of which are incorporated by reference in their entireties.

Materials & Methods

Glucoamylase Activity (AGU)

Glucoamylase activity may be measured in Glucoamylase Units (AGU). The Novo

Glucoamylase Unit (AGU) is defined as the amount of enzyme, which hydrolyzes 1 micromole maltose per minute under the standard conditions 37° C., pH 4.3, substrate: maltose 23.2 mM, buffer: acetate 0.1 M, reaction time 5 minutes.

An autoanalyzer system may be used. Mutarotase is added to the glucose dehydrogenase reagent so that any alpha-D-glucose present is turned into beta-D-glucose. Glucose dehydrogenase reacts specifically with beta-D-glucose in the reaction mentioned above, forming NADH which is determined using a photometer at 340 nm as a measure of the original glucose concentration.

AMG incubation: Substrate: maltose 23.2 mM Buffer: acetate 0.1M pH: 4.30 ± 0.05 Incubation temperature: 37° C. ± 1 Reaction time: 5 minutes Enzyme working range: 0.5-4.0 AGU/mL Color reaction: GlucDH: 430 U/L Mutarotase: 9 U/L NAD: 0.21 mM Buffer: phosphate 0.12M; 0.15M NaCl pH: 7.60 ± 0.05 Incubation temperature: 37° C. ± 1 Reaction time: 5 minutes Wavelength: 340 nm Alpha-amylase Activity (KNU)

Alpha-amylase activity may be determined using potato starch as substrate. This method is based on the break-down of modified potato starch by the enzyme, and the reaction is followed by mixing samples of the starch/enzyme solution with an iodine solution. Initially, a blackish-blue color is formed, but during the break-down of the starch the blue color gets weaker and gradually turns into a reddish-brown, which is compared to a colored glass standard.

One Kilo Novo alpha amylase Unit (KNU) is defined as the amount of enzyme which, under standard conditions (i.e., at 37° C.+/−0.05; 0.0003 M Ca²⁺; and pH 5.6) dextrinizes 5260 mg starch dry substance Merck Amylum solubile.

Acid Alpha-amylase Activity (AFAU)

The activity of an acid alpha-amylase may be measured in AFAU (Acid Fungal Alpha-amylase Units) or FAU-F. Acid alpha-amylase activity may be measured in AFAU (Acid Fungal Alpha-amylase Units), which are determined relative to an enzyme standard. 1 AFAU is defined as the amount of enzyme which degrades 5.260 mg starch dry matter per hour under the below mentioned standard conditions.

Acid alpha-amylase, an endo-alpha-amylase (1,4-alpha-D-glucan-glucanohydrolase, EC 3.2.1.1) hydrolyzes alpha-1,4-glucosidic bonds in the inner regions of the starch molecule to form dextrins and oligosaccharides with different chain lengths. The intensity of color formed with iodine is directly proportional to the concentration of starch. Amylase activity is determined using reverse colorimetry as a reduction in the concentration of starch under the specified analytical conditions.

Standard conditions/reaction conditions: Substrate: Soluble starch, approx. 0.17 g/L Buffer: Citrate, approx. 0.03M Iodine (I₂): 0.03 g/L CaCl₂: 1.85 mM pH: 2.50 ± 0.05 Incubation temperature: 40° C. Reaction time: 23 seconds Wavelength: 590 nm Enzyme concentration: 0.025 AFAU/mL Enzyme working range: 0.01-0.04 AFAU/mL Determination of FAU-F

FAU-F Fungal Alpha-Amylase Units (Fungamyl) is measured relative to an enzyme standard of a declared strength.

Reaction conditions Temperature  37° C. pH 7.15 Wavelength 405 nm Reaction time  5 min Measuring time  2 min Protease Assay Method—AU(RH)

Proteolytic activity may be determined with denatured hemoglobin as substrate. In the Anson-Hemoglobin method for the determination of proteolytic activity denatured hemoglobin is digested, and the undigested hemoglobin is precipitated with trichloroacetic acid (TCA). The amount of TCA soluble product is determined with phenol reagent, which gives a blue color with tyrosine and tryptophan.

One Anson Unit (AU-RH) is defined as the amount of enzyme which under standard conditions (i.e., 25° C., pH 5.5 and 10 minutes reaction time) digests hemoglobin at an initial rate such that there is liberated per minute an amount of TCA soluble product which gives the same color with phenol reagent as one milliequivalent of tyrosine.

The AU(RH) method is described in EAL-SM-0350 and is available from Novozymes A/S Denmark on request.

Protease Assay Method (LAPU)

One Leucine Amino Peptidase Unit (LAPU) is the amount of enzyme which decomposes 1 microM substrate per minute at the following conditions: 26 mM of L-leucine-p-nitroanilide as substrate, 0.1 M Tris buffer (pH 8.0), 37° C., 10 minutes reaction time.

LAPU is described in EB-SM-0298.02/01 available from Novozymes A/S Denmark on request.

Maltogenic Amylase Activity (MANU)

One MANU (Maltogenic Amylase Novo Unit) is the amount of enzyme required to release one micromole of maltose per minute at a concentration of 10 mg of maltotriose (Sigma M 8378) substrate per ml of 0.1 M citrate buffer, pH 5.0 at 37° C. for 30 minutes.

Asparaginase Activity

Stock Solutions

50 mM Tris buffer, pH 8.6

189 mM L-Asparagine solution

1.5 M Trichloroacetic Acid (TCA)

Nessler's reagent, Aldrich Stock No. 34,514-8 (Sigma-Aldrich, St. Louis, Mo. USA)

Asparaginase, Sigma Stock No. A4887 (Sigma-Aldrich, St. Louis, Mo. USA)

Assay

Enzyme Reaction:

500 microliters buffer

100 microliters L-asparagine solution

350 microliters water are mixed and equilibrated to 37° C.

100 microliters of enzyme solution is added and the reactions are incubated at 37° C. for 30 minutes.

The reactions are stopped by placing on ice and adding 50 microliters of 1.5 M TCA.

The samples are mixed and centrifuged for 2 minutes at 20,000×g

Measurement of Free Ammonium:

50 microliters of the enzyme reaction is mixed with 100 microliters of water and 50 microliters of Nessler's reagent. The reaction is mixed and absorbance at 436 nm is measured after 1 minute.

EXAMPLES Example 1 Use of Asparaginase or Amino Acid Oxidase in a Simultaneous Saccharification and Fermentation Process

Corn flour was mixed with tap water in a water bath to achieve a total solids concentration between 30 and 32%. The corn slurry was mixed well to avoid formation of dough balls while raising the temperature to 50° C. Once the corn slurry was heated to 50° C., an asparaginase (500 ppm ACRYLAWAY®/gram dry solids) or a Bothrops atrox amino acid oxidase (Sigma A-3016, 12 micromoles/min/mg protein/g) and an alpha-amylase (0.02% LIQUOZYME SODS® (Novozymes)) was added to the corn mash prior to liquefaction. A control was run with alpha-amylase only. The corn mashes were incubated at 50° C. for one hour with continuous mixing. The temperature was elevated to 85° C. and maintained for two hours to allow for optimal starch liquefaction. The liquefied mashes were then cooled to room temperature.

Detection of Maillard Products

To detect the effectiveness of the asparaginase and the amino acid oxidase to reduce Maillard products, samples were collected at the end of liquefaction. These samples were centrifuged at 1942×g for 20 minutes. The supernatants were transferred to microcentrifuge tubes and further centrifuged at 14560×g for 10 minutes. The supernatants were filtered through a 0.45 micron filter, and 200 microliters of the filtered supernatants were pipetted into a microtiter plate well. The fluorescence intensity was measured by exciting the samples with 360 nm wavelength and setting the emissions detection at 460 nm. Fluorescence intensity (FI) measurement was carried out using a Safire model microtiter plate reader with the software XFLUOR4 Version V4.50 (Tecan Co.). The samples were diluted with distilled water to obtain absorption of 0.05 to 0.1 at 460 nm prior to measuring emission.

The fluorescence intensity measured for each sample is provided in Table 1:

Fluorescence Intensity Control Asparaginase Amino Acid Oxidase 12,250 3,750 1,125

The results show that the use of an asparaginase or amino acid oxidase significantly reduced the amount of Maillard product produced.

Sample Preparation and HLPC Quantification of Ethanol in Corn Fermentations

The cooled, liquefied corn slurries were transferred to fermentation vessels and appropriate amounts of a glucoamylase (SPIRIZYME FUEL®), urea (500 to 1000 ppm) and yeast were added to saccharify the dextrans and ferment the reducing sugars. The simultaneous saccharification and fermentation was carried out at 32° C. to completion 66 hours.

Samples were removed from the fermentations with a wide mouth pipette, and each sample was acidified with 10 microliters of 40% sulfuric acid solution/5 grams of sample to stop the fermentation. The samples were centrifuged for 10 minutes at 1942×g to separate the supernatant and solids. The samples were filtered through a 0.45 micron filter, and ten microliters of the filtered supernatants were analyzed by HPLC using an HPX-787H column (Bio-Rad) heated to 65° C. with a mobile phase of 5 mM sulfuric acid at a flow rate of 0.6 ml/min, with refractive index detection at 50° C.

The amount of ethanol obtained in each fermentation process is provided in Table 2:

TABLE 2 LIQUOZYME LIQUOZYME Control (LIQUOZYME SODS ® plus SODS ® plus SCDS ®) ACRYLAWAY ® amino acid oxidase 12.80 +/− 0.05% w/v 13.50 +/− 0.01% w/v 13.20 +/− 0.03% w/v

The results show that that a greater amount of ethanol was produced in a simultaneous saccharification and fermentation process of corn pre-liquefied with Liquozyme SODS® and ACRYLAWAY® or LIQUOZYME SODS® and amino acid oxidase compared to LIQUOZYME SODS® alone.

Example 2 Use of Asparaginase (ACRYLAWAY®) for Ethanol Production from Raw or Clarified Sugarcane Juice

Sugarcane juice was incubated for 1 hour at 50° C. with or without 50 ppm ACRYLAWAAY® (v/v).

Detection of Maillard Products

Molasses samples were diluted to 20 Brix with distilled water. The diluted molasses samples were filtered through a 0.45 micron filter, and 200 microliters of the filtered molasses were pipetted into a microtiter plate well. The fluorescence intensity was measured by exciting samples with 360 nm wavelength and set emissions detection at 460 nm. Fluorescence intensity (FI) measurement was carried out using a TECAN Safire model microtiter plate reader with the software XFLUOR4 Version V4.50. The samples were diluted with distilled water to obtain absorption of 0.05 to 0.1 at 460 nm prior to measuring emission.

High levels of Maillard products were detected in all molasses samples screened.

Sugarcane Juice Fermentations

Sugarcane juices obtained from different steps in the industrial process (raw juice, juice clarified for sugar production, and juice clarified for ethanol production) were treated with 50 ppm ACRYLAWAY® at 50° C. for 1 hour and subsequently submitted to an evaporation step in a boiling bath prior to fermentation. Five ml of evaporated samples were transferred in replicates for fermentation to 15 ml flip-cap Nunc centrifuge tubes with holes drilled to release CO₂. A 6° Brix solution was prepared from molasses to propagate Red Star yeast: 12 grams of yeast per 80 grams of 6° Brix diluted molasses. Penicillin was added to the solution at 3 mg/L, and the solution was stirred for approximately 16 hours at room temperature. The following morning each fermentation tube containing 5 ml of sample was dosed with 2 ml of yeast propagate and vortexed. Fermentation was carried out at 32° C. for 8 hours. The samples were acidified with 75 microliters of 40% H₂SO₄ to stop the fermentation, and subjected to HPLC analysis.

The amount of ethanol obtained in each fermentation process is provided in Table 3:

TABLE 3 Juice Clarified Juice Clarified for Sugar for Ethanol Raw Juice Production Production With Without With Without With Without Asparaginase Asparaginase Asparaginase Asparaginase Asparaginase Asparaginase 74.5 +/− 0.47 g/l 72.2 +/− 0.09 g/l 73.8 +/− 0.25 g/l 71.7 +/− 0.1 g/l 75.0 +/− 0.73 g/l 73.7 +/− 0.58 g/l

HPLC analysis showed an increased ethanol yield was achieved in each sample treated with an asparaginase.

The present invention is further described in the following numbered paragraphs:

-   [1]. A process of producing a fermentation product, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase;

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(c) fermenting the sugar using a fermenting organism to produce the fermentation product.

-   [2]. The process of paragraph [1], wherein the starch-containing     material is liquefied to the dextrin in the presence of an     asparaginase. -   [3]. The process of paragraph [2], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [4]. The process of paragraph [2], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [5]. The process of any of paragraphs [1]-[4], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an arginase. -   [6]. The process of any of paragraphs [1]-[5], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an amino acid oxidase. -   [7]. The process of paragraph [6], wherein the amino acid oxidase is     an enzyme of EC 1.4.3.2. -   [8]. The process of paragraph [6], wherein the amino acid oxidase is     an enzyme of EC 1.4.3.3. -   [9]. A process of producing a fermentation product, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase;

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme; and

(d) fermenting the sugar using a fermenting organism to produce the fermentation product.

-   [10]. The process of paragraph [9], wherein the starch-containing     material is treated with an asparaginase at a temperature of 20-75°     C., e.g., 25-65° C. or 40-60° C. -   [11]. The process of paragraph [10], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [12]. The process of paragraph [10], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [13]. The process of any of paragraphs [9]-[12], wherein the     starch-containing material is treated with an arginase at a     temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [14]. The process of any of paragraphs [9]-[13], wherein the     starch-containing material is treated with an amino acid oxidase at     a temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [15]. The process of paragraph [14], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [16]. The process of paragraph [14], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [17]. The process of any of paragraphs [1]-[16], further comprising     recovering the fermentation product. -   [18]. A process of producing a sugar, comprising:

(a) liquefying a starch-containing material to a dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) saccharifying the dextrin to a sugar with a saccharifying enzyme.

-   [19]. The process of paragraph [18], wherein the sugar is maltose. -   [20]. The process of paragraph [18], wherein the sugar is glucose. -   [21]. The process of paragraph [20], further comprising converting     glucose to fructose. -   [22]. The process of any of paragraphs [18]-[21], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an asparaginase. -   [23]. The process of paragraph [22], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [24]. The process of paragraph [22], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [25]. The process of any of paragraphs [18]-[24], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an arginase. -   [26]. The process of any of paragraphs [18]-[25], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an amino acid oxidase. -   [27]. The process of paragraph [26], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [28]. The process of paragraph [26], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [29]. A process of producing a sugar, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase; and

(c) saccharifying the dextrin to a sugar with a saccharifying enzyme.

-   [30]. The process of paragraph [29], wherein the sugar is maltose. -   [31]. The process of paragraph [29], wherein the sugar is glucose. -   [32]. The process of paragraph [31], further comprising converting     glucose to fructose. -   [33]. The process of any of paragraphs [29]-[32], wherein the     starch-containing material is treated with an asparaginase at a     temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [34]. The process of paragraph [33], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [35]. The process of paragraph [33], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [36]. The process of any of paragraphs [29]-[35], wherein the     starch-containing material is treated with an arginase at a     temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [37]. The process of any of paragraphs [29]-[36], wherein the     starch-containing material is treated with an amino acid oxidase at     a temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [38]. The process of paragraph [37], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [39]. The process of paragraph [37], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [40]. The process of any of paragraphs [18]-[39], further comprising     recovering the sugar. -   [41]. The process of any of paragraphs [21]-[28] and [32]-[40],     further comprising recovering the fructose. -   [42]. A process of producing a dextrin, comprising

(a) liquefying a starch-containing material to the dextrin with an alpha-amylase in the presence of an amino acid oxidase, an arginase, and/or an asparaginase.

-   [43]. The process of paragraph [42], wherein the starch-containing     material is liquefied to the dextrin in the presence of an     asparaginase. -   [44]. The process of paragraph [43], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [45]. The process of paragraph [43], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [46]. The process of any of paragraphs [42]-[45], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an arginase. -   [47]. The process of any of paragraphs [42]-[46], wherein the     starch-containing material is liquefied to the dextrin in the     presence of an amino acid oxidase. -   [48]. The process of paragraph [47], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [49]. The process of paragraph [47], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [50]. A process of producing a dextrin, comprising:

(a) treating a starch-containing material with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) liquefying the treated starch-containing material to a dextrin with an alpha-amylase.

-   [51]. The process of paragraph [50], wherein the starch-containing     material is treated with an asparaginase at a temperature of 20-75°     C., e.g., 25-65° C. or 40-60° C. -   [52]. The process of paragraph [51], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [53]. The process of paragraph [51], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [54]. The process of any of paragraphs [50]-[53], wherein the     starch-containing material is treated with an arginase at a     temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [55]. The process of any of paragraphs [50]-[54], wherein the     starch-containing material is treated with an amino acid oxidase at     a temperature of 20-75° C., e.g., 25-65° C. or 40-60° C. -   [56]. The process of paragraph [55], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [57]. The process of paragraph [55], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [58]. The process of any of paragraphs [42]-[57], further comprising     recovering the dextrin. -   [59]. The process of any of paragraphs [1]-[58], wherein the     starch-containing material is liquefied to a dextrin at a     temperature of 65-110° C., e.g., 80-100° C. or 80-90° C. -   [60]. The process of any of paragraphs [1]-[59], wherein the     liquefaction comprises jet-cooking at a temperature between 95-140°     C. -   [61]. The process of any of paragraphs [1]-[41] and 59-60, further     comprising pre-saccharification of typically 40-90 minutes at a     temperature between 20-75° C., preferably 25-65° C. -   [62]. The process of any of paragraphs [1]-[41] and [59]-[61],     wherein the saccharification is carried out at a temperature in the     range of 20-75° C., preferably 25-65° C. -   [63]. The process of any of paragraphs [1]-[41] and [59]-[62],     wherein the saccharifying enzyme is a beta-amylase, glucoamylase, or     maltogenic alpha-amylase. -   [64]. The process of any of paragraphs [1]-[41] and [59]-[63],     wherein the dextrin is saccharified to the sugar with a     saccharifying enzyme and a pullulanase and/or isoamylase. -   [65]. The process of any of paragraphs [1]-[41] and [59]-[64],     wherein the saccharification and/or the fermentation are carried out     in the presence of a protease. -   [66]. The process of any of paragraphs [1]-[41] and [59]-[65],     wherein the saccharification and fermentation are performed     simultaneously. -   [67]. The process of paragraph [66], wherein the saccharification     and fermentation are carried out at a temperature of 20-40° C. -   [68]. The process of any of paragraphs [1]-[67], wherein the     starch-containing material is selected from the group consisting of     barley, beans, cassava, cereals, corn, milo, peas, potatoes, rice,     rye, sago, sorghum, sweet potatoes, tapioca, wheat, and whole     grains, or any mixture thereof. -   [69]. A process of producing a fermentation product, comprising     converting a starch-containing material to a dextrin with an     alpha-amylase; saccharifying the dextrin to a sugar with a     glucoamylase; and fermenting the sugar using a fermenting organism     in the presence of an amino acid oxidase, an arginase, and/or an     asparaginase in a single step at a temperature below the initial     gelatinization temperature of the starch-containing material. -   [70]. The process of any of paragraphs [1]-[17] and [59]-[69],     wherein the fermentation product is selected from the group     consisting of alcohols (e.g., butanol, ethanol, methanol,     1,3-propanediol); organic acids (e.g., acetic acid, citric acid,     itaconic acid, gluconic acid, gluconate, lactic acid, succinic acid,     2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids     (e.g., glutamic acid); gases (e.g., H₂ and CO₂), and more complex     compounds, including, for example, antibiotics (e.g., penicillin and     tetracycline); enzymes; vitamins (e.g., riboflavin, B₁₂,     beta-carotene); and hormones. -   [71]. The process of paragraph [70], wherein the fermentation     product is ethanol. -   [72]. The process of any of paragraphs [1]-[17] and [59]-[71],     wherein the fermenting organism is a yeast. -   [73]. A process of producing a fermentation product, comprising

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) producing molasses from the treated plant extract;

(c) diluting the molasses; and

(d) fermenting the diluted molasses with a fermenting organism to produce the fermentation product.

-   [74]. The process of paragraph [73], wherein the plant extract is     treated with an asparaginase. -   [75]. The process of paragraph [74], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [76]. The process of paragraph [74], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [77]. The process of any of paragraphs [73]-[76], wherein the plant     extract is treated with an arginase. -   [78]. The process of any of paragraphs [73]-[77], wherein the plant     extract is treated with an amino acid oxidase. -   [79]. The process of paragraph [78], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [80]. The process of paragraph [78], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [81]. The process of any of paragraphs [73]-[80], wherein the plant     extract is raw sugarcane juice or clarified sugarcane juice. -   [82]. The process of any of paragraphs [73]-[81], wherein the     production of molasses comprises

(x) clarification of the plant extract;

(y) concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup; and

(z) crystallization of sucrose from the syrup to form the molasses.

-   [83]. The process of any of paragraphs [73]-[82], wherein step (a)     occurs at any time prior to evaporation. -   [84]. The process of paragraph [83], wherein step (a) occurs during     juice extraction, crushing, juice recovery, and/or juice     clarification. -   [85]. A process of producing a fermentation product, comprising:

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) fermenting the treated plant extract with a fermenting organism to produce the fermentation product.

-   [86]. The process of paragraph [85], wherein the plant extract is     treated with an asparaginase. -   [87]. The process of paragraph [86], wherein the asparaginase is an     enzyme of EC 3.5.1.1. -   [88]. The process of paragraph [86], wherein the asparaginase is an     enzyme of EC 3.5.1.38. -   [89]. The process of any of paragraphs [85]-[88], wherein the plant     extract is treated with an arginase. -   [90]. The process of any of paragraphs [85]-[89], wherein the plant     extract is treated with an amino acid oxidase. -   [91]. The process of paragraph [90], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.2. -   [92]. The process of paragraph [90], wherein the amino acid oxidase     is an enzyme of EC 1.4.3.3. -   [93]. The process of any of paragraphs [85]-[92], wherein the plant     extract is raw sugarcane juice or clarified sugarcane juice. -   [94]. The process of any of paragraphs [73]-[93], further comprising     recovering the fermentation product. -   [95]. The process of any of paragraphs [73]-[94], wherein the     fermentation product is selected from the group consisting of     alcohols (e.g., butanol, ethanol, methanol, 1,3-propanediol);     organic acids (e.g., acetic acid, citric acid, itaconic acid,     gluconic acid, gluconate, lactic acid, succinic acid,     2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids     (e.g., glutamic acid); gases (e.g., H₂ and CO₂), and more complex     compounds, including, for example, antibiotics (e.g., penicillin and     tetracycline); enzymes; vitamins (e.g., riboflavin, B₁₂,     beta-carotene); and hormones. -   [96]. The process of paragraph [95], wherein the fermentation     product is ethanol. -   [97]. The process of any of paragraphs [73]-[96], wherein the     fermenting organism is a yeast. -   [98]. A process of producing a sugar, comprising:

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; and

(b) recovering the sugar from the plant extract.

-   [99]. The process of paragraph [98], wherein the sugar is fructose,     galactose, glucose, maltose, or sucrose. -   [100]. A process of producing sucrose, comprising:

(a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase;

(b) clarification of the plant extract;

(c) concentration of sugars found in the clarified plant extract (e.g., by evaporation) to form a syrup containing sucrose;

(d) crystallization of sucrose from the syrup; and

(e) recovering sucrose.

-   [101]. The process of any of paragraphs [98]-[100], wherein the     plant extract is treated with an asparaginase. -   [102]. The process of paragraph [101], wherein the asparaginase is     an enzyme of EC 3.5.1.1. -   [103]. The process of paragraph [101], wherein the asparaginase is     an enzyme of EC 3.5.1.38. -   [104]. The process of any of paragraphs [98]-[103], wherein the     plant extract is treated with an arginase. -   [105]. The process of any of paragraphs [98]-[104], wherein the     plant extract is treated with an amino acid oxidase. -   [106]. The process of paragraph [105], wherein the amino acid     oxidase is an enzyme of EC 1.4.3.2. -   [107]. The process of paragraph [105], wherein the amino acid     oxidase is an enzyme of EC 1.4.3.3. -   [108]. The process of any of paragraphs [98]-[107], wherein the     plant extract is raw sugarcane juice or clarified sugarcane juice. -   [109]. The process of any of paragraphs [98]-[108], wherein step (a)     occurs at any time prior to evaporation. -   [110]. The process of paragraph [109], wherein step (a) occurs     during juice extraction, crushing, juice recovery, and/or juice     clarification. -   [111]. The process of any of paragraphs [98]-[110], wherein raw     sugarcane juice is treated with an asparaginase. -   [112]. The process of any of paragraphs [98]-[111], wherein raw     sugarcane juice is treated with an arginase. -   [113]. The process of any of paragraphs [98]-[112], wherein raw     sugarcane juice is treated with an amino acid oxidase. -   [114]. The process of any of paragraphs [98]-[113], wherein     sugarcane juice clarified for sugar production is treated with an     asparaginase. -   [115]. The process of any of paragraphs [98]-[114], wherein     sugarcane juice clarified for sugar production is treated with an     arginase. -   [116]. The process of any of paragraphs [98]-[115], wherein     sugarcane juice clarified for sugar production is treated with an     amino acid oxidase. -   [117]. The process of any of paragraphs [98]-[116], wherein     sugarcane juice clarified for ethanol production is treated with an     asparaginase. -   [118]. The process of any of paragraphs [98]-[117], wherein     sugarcane juice clarified for ethanol production is treated with an     arginase. -   [119]. The process of any of paragraphs [98]-[118], wherein     sugarcane juice clarified for ethanol production is treated with an     amino acid oxidase. -   [120]. The process of any of paragraphs [73]-[119], wherein the     plant extract is selected from the group consisting of sweet     sorghum, sugar beets, sugar cane, or any mixture thereof. -   [121]. The process of any of paragraphs [73]-[120], wherein the raw     juice is clarified for sugar and/or ethanol production at a pH of     7.5-9, e.g., 8-9. -   [122]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 1, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 1 that has asparaginase activity.

-   [123]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 2, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 2 that has asparaginase activity.

-   [124]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 3, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 3 that has asparaginase activity.

-   [125]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 4, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 4 that has asparaginase activity.

-   [126]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 5, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 5 that has asparaginase activity.

-   [127]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 6, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 6 that has asparaginase activity.

-   [128]. The process of any of paragraphs [1]-[121], wherein the     asparaginase

(a) has at least 70% sequence identity to SEQ ID NO: 7, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 7 that has asparaginase activity.

-   [129]. The process of any of paragraphs [1]-[121], wherein the     asparaginase is a thermostable asparaginase. -   [130]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 8, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 8 that has amino acid oxidase activity.

-   [131]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 9, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 9 that has amino acid oxidase activity.

-   [132]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 10, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 10 that has amino acid oxidase activity.

-   [133]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 11, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 11 that has amino acid oxidase activity.

-   [134]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 12, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 12 that has amino acid oxidase activity.

-   [135]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 13, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 13 that has amino acid oxidase activity.

-   [136]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase

(a) has at least 70% sequence identity to SEQ ID NO: 14, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 14 that has amino acid oxidase activity.

-   [137]. The process of any of paragraphs [1]-[129], wherein the amino     acid oxidase is a thermostable amino acid oxidase. -   [138]. The process of any of paragraphs [1]-[137], wherein the     arginase

(a) has at least 70% sequence identity to SEQ ID NO: 15, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 15 that has amino acid oxidase activity.

-   [139]. The process of any of paragraphs [1]-[137], wherein the     arginase

(a) has at least 70% sequence identity to SEQ ID NO: 16, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 16 that has amino acid oxidase activity.

-   [140]. The process of any of paragraphs [1]-[137], wherein the     arginase

(a) has at least 70% sequence identity to SEQ ID NO: 17, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 17 that has amino acid oxidase activity.

-   [141]. The process of any of paragraphs [1]-[137], wherein the     arginase

(a) has at least 70% sequence identity to SEQ ID NO: 18, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 18 that has amino acid oxidase activity.

-   [142]. The process of any of paragraphs [1]-[137], wherein the     arginase

(a) has at least 70% sequence identity to SEQ ID NO: 19, e.g., at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% sequence identity; or

(b) is a fragment of SEQ ID NO: 19 that has amino acid oxidase activity.

-   [143]. The process of any of paragraphs [1]-[137], wherein the amino     acid oxidase is a thermostable arginase. -   [144]. A composition comprising (a) an asparaginase, an arginase,     and/or amino acid oxidase, (b) a glucoamylase and (c) an     alpha-amylase. -   [145]. The composition of paragraph [144], which comprises an     asparaginase. -   146. The composition of paragraph [145], which comprises an     asparaginase of EC 3.5.1.1. -   [147]. The composition of paragraph [145], which comprises an     asparaginase of EC 3.5.1.38. -   [148]. The composition of any of paragraphs [144]-[147], which     comprises an arginase. -   [149]. The composition of any of paragraphs [144]-[148], which     comprises an amino acid oxidase. -   [150]. The composition of paragraph [149], which comprises an amino     acid oxidase of EC 1.4.3.2. -   [151]. The composition of paragraph [149], which comprises an amino     acid oxidase of EC 1.4.3.3. -   [152]. The composition of paragraph [144], which comprises an     asparaginase, an arginase, and an amino acid oxidase. -   [153]. The composition of paragraph [152], which comprises an     asparaginase of EC 3.5.1.1. -   [154]. The composition of paragraph [152], which comprises an     asparaginase of EC 3.5.1.38. -   [155]. The composition of any of paragraphs [152]-[154], which     comprises an amino acid oxidase of EC 1.4.3.2. -   [156]. The composition of any of paragraphs [152]-[154], which     comprises an amino acid oxidase of EC 1.4.3.3. -   [157]. The composition of any of paragraphs [144]-[156], further     comprising a pullulanase. 

The invention claimed is:
 1. A process of producing a fermentation product, comprising (a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; (b) producing molasses from the treated plant extract; (c) diluting the molasses; and (d) fermenting the diluted molasses with a fermenting organism to produce the fermentation product.
 2. The process of claim 1, wherein the plant extract is treated with an asparaginase.
 3. The process of claim 2, wherein the asparaginase is an enzyme of EC 3.5.1.1.
 4. The process of claim 2, wherein the asparaginase is an enzyme of EC 3.5.1.38.
 5. The process of claim 1, wherein the plant extract is treated with an arginase.
 6. The process of claim 1, wherein the plant extract is treated with an amino acid oxidase.
 7. The process of claim 6, wherein the amino acid oxidase is an enzyme of EC 1.4.3.2.
 8. The process of claim 6, wherein the amino acid oxidase is an enzyme of EC 1.4.3.3.
 9. The process of claim 1, wherein the plant extract is raw sugarcane juice or clarified sugarcane juice.
 10. The process of claim 1, wherein the production of molasses comprises: clarification of the plant extract; concentration of sugars found in the clarified plant extract to form a syrup; and crystallization of sucrose from the syrup to form the molasses.
 11. A process of producing a fermentation product, comprising (a) treating a plant extract containing amino acid(s) and soluble sugar(s) with an amino acid oxidase, an arginase, and/or an asparaginase; (b) producing molasses from the treated plant extract; (c) diluting the molasses; and (d) fermenting the diluted molasses with a fermenting organism to produce the fermentation product, wherein the plant extract is selected from the group consisting of sweet sorghum extract, sugar beet extract, sugar cane extract, sugar cane juice, clarified sugarcane juice, and combinations thereof.
 12. The process of claim 11, wherein the plant extract is treated with an asparaginase.
 13. The process of claim 11, wherein the asparaginase is an enzyme of EC 3.5.1.1.
 14. The process of claim 11, wherein the asparaginase is an enzyme of EC 3.5.1.38.
 15. The process of claim 11, wherein the plant extract is treated with an arginase.
 16. The process of claim 11, wherein the plant extract is treated with an amino acid oxidase.
 17. The process of claim 11, wherein the plant extract is treated with an arginase.
 18. The process of claim 11, wherein the plant extract is treated with an amino acid oxidase. 